MLX90614 family
Datasheet Single and Dual Zone
Infra Red Thermometer in TO-39

Features and Benefits

Application Examples

Small size, low cost
Easy to integrate
Factory calibrated in wide temperature
range:-40°C…+125˚C for sensor temperature and-70°C…+380˚C for object temperature.
High accuracy of 0.5°C in a wide
temperature range (0°C…+50°C for both Ta
and To)High (medical) accuracy calibration
Measurement resolution of 0.02°C
Single and dual zone versions
SMBus compatible digital interface
Customizable PWM output for continuous
reading
Available in 3V and 5V versions
Simple adaptation for 8V…16V applications
Sleep mode for reduced power
consumption
Different package options for applications
and measurements versatility

High precision non-contact temperature
measurements
Thermal Comfort sensor for Mobile Air
Conditioning control system
Temperature sensing element forresidential, commercial and industrial
building air conditioning
Windshield defogging
Automotive blind angle detection
Industrial temperature control of movingparts
Temperature control in printers andcopiers
Home appliances with temperature control
Healthcare
Livestock monitoring
Movement detection
Multiple zone temperature control – up to
127 sensors can be read via common 2
wires
Thermal relay / alert
Body temperature measurement

Automotive grade

Ordering Information
Part No.
MLX90614

Temperature
Code
E (-40°C...85°C)
K (-40°C…125°C)(1) Supply Voltage/ Accuracy
A - 5V
B - 3VC - Reserved
D - 3V medical accuracy

Example:
MLX90614ESF-BAA-000-TU

REVISION 13 - 13 SEPTEMBER, 2019
3901090614

PackageCode
SF (TO-39)- Option Code
-X X X(1) (2) (3)(2) Number of thermopiles:
A – single zone
B – dual zone
C – gradient compensated** : See page 2Standard
part-000

Packing
form-TU(3) Package options:
A – Standard package
B – Reserved
C – 35° FOV
D/E – Reserved
F – 10° FOV
G – Reserved
H – 12° FOV (refractive lens)I – 5° FOV
K – 13°FOV

MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

1. Functional diagram

2. General Description

MLX90614Axx: Vdd=4.5...5.5V
J1
1 MLX90614
SCL
U1
SCL
Vz

SDA
Vdd
GND

PWM
2 SDA

Vss 4
Vdd
3

C1

0.1uF
CON1
C1 value and type may differ
in different applications
for optimum EMC

MLX90614 connection to SMBus
Figure 1: Typical application schematics

The MLX90614 is an Infra Red thermometer for noncontact temperature measurements.
Both the IR
sensitive thermopile detector chip and the signal
conditioning ASSP are integrated in the same TO-39 can.
Thanks to its low noise amplifier, 17-bit ADC andpowerful DSP unit, a high accuracy and resolution of thethermometer is achieved.
The thermometer comes factory calibrated with a digital
PWM and SMBus (System Management Bus) output.
As a standard, the 10-bit PWM is configured tocontinuously transmit the measured temperature in
range of -20…120˚C, with an output resolution of 0.14˚C.
The factory default POR setting is SMBus.

The MLX90614 is built from 2 chips developed and manufactured by Melexis:
The Infra Red thermopile detector MLX81101
The signal conditioning ASSP MLX90302, specially designed to process the output of IR sensor.
The device is available in an industry standard TO-39 package.
Thanks to the low noise amplifier, high resolution 17-bit ADC and powerful DSP unit of MLX90302 high accuracy andresolution of the thermometer is achieved. The calculated object and ambient temperatures are available in RAM of
MLX90302 with resolution of 0.01°C. They are accessible by 2 wire serial SMBus compatible protocol (0.02°C
resolution) or via 10-bit PWM (Pulse Width Modulated) output of the device.
The MLX90614 is factory calibrated in wide temperature ranges: -40°C…125°C for the ambient temperatureand -70°C…380°C for the object temperature.
The measured value is the average temperature of all objects in the Field Of View of the sensor. The MLX90614 offers
a standard accuracy of ±0.5˚C around room temperatures. A special version for medical applications exists offering an
accuracy of ±0.2˚C in a limited temperature range around the human body temperature.
It is very important for the application designer to understand that these accuracies are only guaranteed andachievable when the sensor is in thermal equilibrium and under isothermal conditions (there are no temperature
differences across the sensor package). The accuracy of the thermometer can be influenced by temperature
differences in the package induced by causes like (among others): Hot electronics behind the sensor, heaters/coolers
behind or beside the sensor or by a hot/cold object very close to the sensor that not only heats the sensing element in
the thermometer but also the thermometer package.
This effect is especially relevant for thermometers with a small FOV like the xxC and xxF as the energy received by thesensor from the object is reduced. Therefore, Melexis has introduced the xCx version of the MLX90614. In these
MLX90614xCx, the thermal gradients are measured internally and the measured temperature is compensated forthem. In this way, the xCx version of the MLX90614 is much less sensitive to thermal gradients, but the effect is nottotally eliminated. It is therefore important to avoid the causes of thermal gradients as much as possible or to shield
the sensor from them.
As a standard, the MLX90614 is calibrated for an object emissivity of 1. It can be easily customized by the customer for
any other emissivity in the range 0.1…1.0 without the need of recalibration with a black body.
The 10-bit PWM is as a standard configured to transmit continuously the measured object temperature for an object
temperature range of -20°C…120°C with an output resolution of 0.14°C. The PWM can be easily customized for
virtually any range desired by the customer by changing the content of 2 EEPROM cells. This has no effect on thefactory calibration of the device.

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

The PWM pin can also be configured to act as a thermal relay (input is To), thus allowing for an easy and cost effective
implementation in thermostats or temperature (freezing / boiling) alert applications. The temperature threshold isuser programmable. In a SMBus system this feature can act as a processor interrupt that can trigger reading all slaves
on the bus and to determine the precise condition.
The thermometer is available in 2 supply voltage options: 5V compatible or 3V (battery) compatible. The 5V can beeasily adopted to operate from a higher supply voltage (8…16V, for example) by use of few external components (refer
to “Applications information” section for details).
An optical filter (long-wave pass) that cuts off the visible and near infra-red radiant flux is integrated in the package toprovide ambient and sunlight immunity. The wavelength pass band of this optical filter is from 5.5…14µm (except for
xCH and xCI type of devices which incorporate uncoated silicon lens).

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

3. Contents
Features and Benefits................................................................
................................................................................................
................................................................................................
................................................................ 1
Application Examples ................................................................
................................................................................................
................................................................................................
................................................................ 1
Ordering Information ................................................................
................................................................................................
................................................................................................
................................................................ 1
1. Functional diagram ................................................................
................................................................................................
................................................................................................
................................................................ 2
2. General Description ................................................................
................................................................................................
...............................................................................................
............................................................... 2
3. Contents ................................................................
................................................................................................
................................................................................................
................................................................................
................................................ 4
4. Glossary of Terms ................................................................
................................................................................................
................................................................................................
..................................................................
.................................. 7
5. Maximum ratings................................................................
................................................................................................
................................................................................................
...................................................................
................................... 7
6. Pin definitions
definitions and descriptions ................................................................
................................................................................................
.............................................................................
............................................. 8
7. Electrical Specifications ................................................................
................................................................................................
.........................................................................................
......................................................... 9
7.1. MLX90614Axx ..................................................................................................................................... 9
7.2. MLX90614Bxx, MLX90614Dxx .......................................................................................................... 11
8. Detailed
Detailed description ................................................................
................................................................................................
............................................................................................
............................................................ 13
8.1. Block diagram.................................................................................................................................... 13
8.2. Signal processing principle ............................................................................................................... 13
8.3. Block description............................................................................................................................... 14
8.3.1. Amplifier ...................................................................................................................................... 14
8.3.2. Supply regulator and POR .......................................................................................................... 14
8.3.3. EEPROM ...................................................................................................................................... 14
8.3.4. RAM ............................................................................................................................................. 178.4. SMBus compatible 2-wire protocol ................................................................................................. 17
8.4.1. Functional description ................................................................................................................ 17
8.4.2. Differences with the standard SMBus specification (reference [1]) ........................................ 18
8.4.3. Detailed description ................................................................................................................... 18
8.4.4. Bit transfer .................................................................................................................................. 19
8.4.5. Commands .................................................................................................................................. 20
8.4.6. SMBus communication examples .............................................................................................. 20
8.4.7. Timing specification .................................................................................................................... 21
8.4.8. Sleep Mode ................................................................................................................................. 22
8.4.9. MLX90614 SMBus specific remarks ........................................................................................... 23
8.5. PWM .................................................................................................................................................. 24

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

8.5.1. Single PWM format..................................................................................................................... 25
8.5.2. Extended PWM format ............................................................................................................... 26
8.5.3. Customizing the temperature range for PWM output ............................................................. 27
8.6. Switching Between PWM / Thermal relay and SMBus communication ........................................ 29
8.6.1. PWM is enabled .......................................................................................................................... 29
8.6.2. Request condition ....................................................................................................................... 29
8.6.3. PWM is disabled ......................................................................................................................... 29
8.7. Computation of ambient and object temperatures ....................................................................... 30
8.7.1. Ambient temperature Ta............................................................................................................ 30
8.7.2. Object temperature To ............................................................................................................... 30
8.7.3. Calculation flow .......................................................................................................................... 31
8.8. Thermal relay .................................................................................................................................... 32
9. Unique Features ................................................................
................................................................................................
................................................................................................
..................................................................
.................................. 33
10. Performance Graphs................................
Graphs................................................................
................................................................................................
..........................................................................................
.......................................................... 34
10.1. Temperature accuracy of the MLX90614 ...................................................................................... 34
10.1.1. Standard accuracy .................................................................................................................... 34
10.1.2. Medical accuracy ...................................................................................................................... 36
10.1.3. Temperature reading dependence on VDD ............................................................................ 36
10.2. Field Of View (FOV) ......................................................................................................................... 38
11. Applications Information ................................................................
................................................................................................
...................................................................................
................................................... 42
11.1. Use of the MLX90614 thermometer in SMBus configuration...................................................... 42
11.2. Use of multiple MLX90614s in SMBus configuration ................................................................... 42
11.3. PWM output operation .................................................................................................................. 42
11.4. Thermal alert / thermostat ............................................................................................................ 43
11.5. High voltage source operation ....................................................................................................... 44
12. Application Comments ................................................................
................................................................................................
......................................................................................
...................................................... 45
13. Standard
Standard information regarding manufacturability of Melexis products with different soldering
processes................................................................
................................................................................................
................................................................................................
............................................................................
............................................ 47
14. ESD Precautions................................................................
................................................................................................
................................................................................................
.................................................................
................................. 47
15. FAQ ................................................................
................................................................................................
................................................................................................
...................................................................................
................................................... 48
16. Package Information................................................................
................................................................................................
..........................................................................................
.......................................................... 50
16.1. MLX90614xxA ................................................................................................................................. 50
16.2. MLX90614xCC ................................................................................................................................. 50

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

16.3. MLX90614xCF ................................................................................................................................. 51
16.4. MLX90614xCH................................................................................................................................. 51
16.5. MLX90614xCI .................................................................................................................................. 52
16.6. MLX90614xCK ................................................................................................................................. 52
16.7. Part marking .................................................................................................................................... 53
16.8. Operating and storage humidity range ......................................................................................... 53
17. Table of figures ................................................................
................................................................................................
................................................................................................
..................................................................
.................................. 54
18. References
References................................
es................................................................
................................................................................................
................................................................................................
.........................................................................
......................................... 55
19. Contact ................................................................
................................................................................................
................................................................................................
..............................................................................
.............................................. 56
20. Disclaimer ................................................................
................................................................................................
................................................................................................
..........................................................................
.......................................... 56

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

4. Glossary of Terms
PTAT
POR
HFO
DSP
FIR
IIR
IR
PWM
DC
FOV
SDA,SCL
Ta
To
ESD
EMC
ASSP
TBD

Proportional To Absolute Temperature sensor (package temperature)
Power On ResetHigh Frequency Oscillator (RC type)
Digital Signal Processing
Finite Impulse Response. Digital filter
Infinite Impulse Response. Digital filter
Infra-Red
Pulse With Modulation
Duty Cycle (of the PWM) ; Direct Current (for settled conditions specifications)Field Of View
Serial DAta, Serial CLock – SMBus compatible communication pins
Ambient Temperature measured from the chip – (the package temperature)
Object Temperature, ‘seen’ from IR sensor
Electro-Static Discharge
Electro-Magnetic Compatibility
Application Specific Standard ProductTo Be DefinedNote: sometimes the MLX90614xxx is referred as “the module”.

5. Maximum ratings
Parameter

MLX90614ESF-Axx

MLX90614ESF-Bxx
MLX90614ESF-Dxx

MLX90614KSF-Axx

Supply Voltage, VDD (over voltage)

7V

5V

7V

Supply Voltage, VDD (operating)

5.5 V

3.6V

5.5V

Reverse Voltage

0.4 V

Operating Temperature Range, TA-40°C…+85°C-40°C…+125°C

Storage Temperature Range, TS-40°C…+125°C-40°C…+125°C

ESD Sensitivity (AEC Q100 002)

2kV

DC current into SCL / Vz (Vz mode)

2 mA

DC sink current, SDA / PWM pin

25 mA

DC source current, SDA / PWM pin

25 mA

DC clamp current, SDA / PWM pin

25 mA

DC clamp current, SCL pin

25 mA
Table 1: Absolute maximum ratings for MLX90614

Exceeding the absolute maximum ratings may cause permanent damage.
Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

6. Pin definitions and descriptions

4 - VSS

1 - SCL / Vz

3 - VDD2 - SDA / PWM

Bottom view
Figure 2: Pin description
Pin Name

Function

SCL / Vz

Serial clock input for 2 wire communications protocol. 5.7V zener is available atthis pin for connection of external bipolar transistor to MLX90614Axx to supply
the device from external 8…16V source.

SDA / PWM

Digital input / output. In normal mode the measured object temperature isavailable at this pin Pulse Width Modulated.
In SMBus compatible mode the pin is automatically configured as open drain
NMOS.

VDD

External supply voltage.

VSS

Ground. The metal can is also connected to this pin.
Table 2: Pin description MLX90614

Note: for +12V (+8…+16V) powered operation refer to the Application information section. For EMC and isothermal
conditions reasons it is highly recommended not to use any electrical connection to the metal can except by the VSS pin.
With the SCL / Vz and PWM / SDA pins operated in 2-wire interface mode, the input Schmidt trigger function is automaticallyenabled.

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

7. Electrical Specifications
7.1. MLX90614Axx
All parameters are valid for TA = 25 ˚C, VDD =5V (unless otherwise specified)Parameter

SymbolTest Conditions

Min

Typ

Max

Units

4.5

5

5.5

V

Supplies
External supply

VDD

Supply current

IDD

No load

1.3

2

mA

Supply current(programming)

IDDpr

No load, erase/write EEPROM
operations

1.5

2.5

mA

Zener voltage

Vz

Iz = 75…1000μA (Ta=room)

5.5

5.7

5.9

V

Zener voltage

Vz(Ta)

Iz = 70…1000μA,
full temperature range

5.15

5.7

6.24

V

POR level

VPOR_upPower-up (full temp range)

1.4

1.75

1.95

V

POR level

VPOR_down

Power –down (full temp range)

1.3

1.7

1.9

V

POR hysteresis
VDD rise time (10% to 90% of
specified supply voltage)
Output valid(result in RAM)VPOR_hys

Full temp range

0.08

0.1

1.15

V

TPOR

Ensure POR signal

20

ms

TvalidAfter POR

Power On Reset

Pulse width modulation

0.25

s

10

bit

1.024

ms

1

PWM resolution

PWMresData band
Factory default, internal oscillator
factory calibrated

PWM output period

PWMT,def

PWM period stability

dPWMTInternal oscillator factory
calibrated, over the entire
operation range and supply voltage-10Output high Level

PWMHI

Isource = 2 mA

VDD-0.2

Output low Level

PWMLO

Isink = 2 mA

Output drive current

IdrivePWM

Vout,H = VDD - 0.8V

7mA

Output sink current

IsinkPWM

Vout,L = 0.8V

13.5

mA

+10

%
V

VSS+0.2

V

Continued on next page

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
Parameter

SymbolTest Conditions
SMBus compatible 2-wire interface

Min

Typ

Max

Units

2

Input high voltage

VIH (Ta, V)

Over temperature and supply

3

V

Input low voltage

VIL (Ta, V)

Over temperature and supply

0.6

V

Output low voltage

VOL

Over temperature and supply, Isink
= 2mA

0.2

V

SCL leakage

ISCL, leak

VSCL=4V, Ta=+85°C

30

μA

SDA leakage

ISDA, leak

VSDA=4V, Ta=+85°C

0.3

μA

SCL capacitance

CSCL

10

pF

SDA capacitance

CSDA

Slave addressSA

Factory default

Wake up request

twake

SDA low

33

ms

SMBus RequesttREQ

SCL low

1.44

ms

10

pF
hex

5A

Timeout, low

Timeout,L

SCL low

27

33

ms

Timeout, highTimeout,H

SCL high

45

55

μs

Acknowledge setup time

Tsuac(MD)8-th SCL falling edge, Master

1.5

μs

Acknowledge hold timeThdac(MD)9-th SCL falling edge, Master

1.5

μs

Acknowledge setup time

Tsuac(SD)

8-th SCL falling edge, Slave

2.5

μs

Acknowledge hold timeThdac(SD)

9-th SCL falling edge, Slave

1.5

μs

EEPROM
Data retention

Ta = +85°C

10

years

Erase/write cycles

Ta = +25°C

100,000

Times

Erase/write cycles

Ta = +125°C

10,000Times

Erase cell time

Terase5ms

Write cell time

Twrite5ms

Table 3: Electrical specification MLX90614Axx
Notes: All the communication and refresh rate timings are given for the nominal calibrated HFO frequency and will varywith this frequency’s variations.
1. With large capacitive load lower PWM frequency is recommended. Thermal relay output (when configured) has
the PWM DC specification and can be programmed as push-pull, or NMOS open drain. PWM is free-running, power-up
factory default is SMBus, refer to section 8.6, “Switching between PWM and SMBus communication” for more details.
2. For SMBus compatible interface on 12V application refer to Application information section. SMBus compatible
interface is described in details in the SMBus detailed description section. Maximum number of MLX90614 devices on one bus
is 127, higher pull-up currents are recommended for higher number of devices, faster bus data transfer rates, and increased
reactive loading of the bus.
MLX90614 is always a slave device on the bus. MLX90614 can work in both low-power and high-power SMBus
communication.
All voltages are referred to the Vss (ground) unless otherwise noted.
Sleep mode is not available on the 5V version (MLX90614Axx).

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

7.2. MLX90614Bxx, MLX90614Dxx
All parameters are valid for TA = 25 ˚C, VDD =3V (unless otherwise specified)Parameter

SymbolTest Conditions

Min

External supply

VDD

Supply current

IDD

No loadSupply current(programming)

IDDpr

No load, erase / write EEPROM
operations

Typ

Max

Units

3

3.6

V

1.3

2

mA

1.5

2.5

mA

Supplies
2.6

Sleep mode current

Isleepno load

1

2.5

5

μA

Sleep mode current

Isleep

Full temperature range

1

2.5

6

μA

POR level

VPOR_upPower-up (full temp range)

1.4

1.75

1.95

V

Power On Reset
POR level

VPOR_down

Power –down (full temp range)

1.3

1.7

1.9

V

POR hysteresis
VDD rise time
(10% to 90% of
specified supply voltage)

VPOR_hys

Full temp range

0.08

0.1

1.15

V

TPOR

Ensure POR signal

20ms

Output valid

TvalidAfter POR

Pulse width modulation

0.25

s

1

PWM resolution

PWMresData band

10bit

PWM output period

PWMT,def

Factory default, internal oscillator
factory calibrated

1.024

ms

PWM period stability

dPWMTInternal oscillator factory
calibrated, over the entire
operation range and supply voltage-10Output high Level

PWMHI

Isource = 2 mA

VDD-0.25

Output low Level

PWMLO

Isink = 2 mA

Output drive current

IdrivePWM

Vout,H = VDD - 0.8V

4.5

mA

Output sink current

IsinkPWM

Vout,L = 0.8V

11

mA

+10

%
V

VSS+0.25

V

Continued on next page

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
Parameter

SymbolTest Conditions
SMBus compatible 2-wire interface

Min

Typ

Max

Units

2

Input high voltage

VIH(Ta,V)

Over temperature and supply

VDD-0.1

V

Input low voltage

VIL(Ta,V)

Over temperature and supply

0.6

V

Output low voltage

VOL

Over temperature and supply,
Isink = 2mA

0.25

V

SCL leakage

ISCL,leak

VSCL=3V, Ta=+85°C

20

μA

SDA leakage

ISDA,leak

VSDA=3V, Ta=+85°C

0.25

μA

SCL capacitance

CSCL

10

pF

SDA capacitance

CSDA

Slave addressSA

Factory default

Wake up request

twake

SDA low

33

ms

SMBus RequesttREQ

SCL low

1.44

ms

10
5A

pF
hex

Timeout,low

Timeout,L

SCL low

27

33

ms

Timeout, highTimeout,H

SCL high

45

55

μs

Acknowledge setup time

Tsuac(MD)8-th SCL falling edge, Master

1.5

μs

Acknowledge hold timeThdac(MD)9-th SCL falling edge, Master

1.5

μs

Acknowledge setup time

Tsuac(SD)

8-th SCL falling edge, Slave

2.5

μs

Acknowledge hold timeThdac(SD)

9-th SCL falling edge, Slave

1.5

μs

EEPROM
Data retention

Ta = +85°C

10

years

Erase/write cycles

Ta = +25°C

100,000

Times

Ta = +125°C

10,000Erase/write cycles

Times

Erase cell time

Terase5ms

Write cell time

Twrite5ms

Table 4: Electrical specification MLX90614Bxx, Dxx
Note: refer to MLX90614Axx notes.

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

8. Detailed description
8.1. Block diagram

81101
OPA

ADC

DSP

PWM

t°

STATE MACHINE

Voltage
Regulator

90302

Figure 3: Block diagram

8.2. Signal processing principle
The operation of the MLX90614 is controlled by an internal state machine, which controls the measurements andcalculations of the object and ambient temperatures and does the post-processing of the temperatures to output themthrough the PWM output or the SMBus compatible interface.
The ASSP supports 2 IR sensors (second one not implemented in the MLX90614xAx).The output of the IR sensors is
amplified by a low noise low offset chopper amplifier with programmable gain, converted by a Sigma Delta modulator
to a single bit stream and fed to a powerful DSP for further processing. The signal is treated by programmable (bymeans of EEPROM contend) FIR and IIR low pass filters for further reduction of the band width of the input signal toachieve the desired noise performance and refresh rate. The output of the IIR filter is the measurement result and isavailable in the internal RAM. 3 different cells are available: One for the on-board temperature sensor and 2 for the IR
sensors.
Based on results of the above measurements, the corresponding ambient temperature Ta and object temperatures To
are calculated. Both calculated temperatures have a resolution of 0.01˚C. The data for Ta and To can be read in two
ways: Reading RAM cells dedicated for this purpose via the 2-wire interface (0.02°C resolution, fixed ranges), or
through the PWM digital output (10 bit resolution, configurable range).
In the last step of the measurement cycle, the measured Ta and To are rescaled to the desired output resolution of thePWM) and the recalculated data is loaded in the registers of the PWM state machine, which creates a constantfrequency with a duty cycle representing the measured data.

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39

8.3. Block description
8.3.1. Amplifier
A low noise, low offset amplifier with programmable gain is used for amplifying the IR sensor voltage. By carefully
designing the input modulator and balanced input impedance, the max offset of the system is 0.5μV.

8.3.2. Supply regulator and POR
The module can operate from 3 different supplies:
VDD = 5V

MLX90614Axx

VDD = 3V

MLX90614Bxx (battery or regulated supply)

VDD = 8V…16V
MLX90614Axx few external components are necessary please refer to “Applications information”
section for information about adopting higher voltage supplies.

The Power On Reset (POR) is connected to Vdd supply. The on-chip POR circuit provides an active (high) level of the POR
signal when the Vdd voltage rises above approximately 0.5V and holds the entire MLX90614 in reset until the Vdd is higher
than the specified POR threshold VPOR. During the time POR is active, the POR signal is available as an open drain at the
PWM/SDA pin. After the MLX90614 exits the POR condition, the function programmed in EEPROM takes precedence for thatpin.

8.3.3. EEPROM
A limited number of addresses in the EEPROM memory can be changed by the customer. The whole EEPROM can be readthrough the SMBus interface.
EEPROM (32X16)
Name
Tomax
Tomin
PWMCTRL
Ta range
Emissivity
Config Register1
Melexis reserved…
Melexis reserved
SMBus address (LSByte only)
Melexis reserved
Melexis reserved…
Melexis reserved
Melexis reserved
Melexis reserved
Melexis reserved
ID number
ID number
ID number
ID number

Address

Write access

0x00
0x01
0x02
0x03
0x04
0x05
0x06
…
0x0D
0x0E
0x0F
0x10
…
0x18
0x19
0x1A
0x1B
0x1C
0x1D
0x1E
0x1F

Yes
Yes
Yes
Yes
Yes
Yes
No
…
No
Yes
Yes
No
…
No
Yes
No
No
No
No
No
No

Table 5: EEPROM table
The addresses Tomax, Tomin and Ta range are for customer dependent object and ambient temperature ranges. For details see
section 8.5.3 below in this document
The address Emissivity contains the object emissivity (factory default 1.0 = 0xFFFF), 16 bit.

εEmissivity = dec2hex[ round( 65535 x ) ]Where dec2hex[ round( X ) ] represents decimal to hexadecimal conversion with round-off to nearest value (not truncation).

εIn this case the physical emissivity values are = 0.1…1.0.
Erase (write 0) must take place before write of desired data is made.

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PWM period configuration: Period in extended PWM mode is twice the period in single PWM mode.
In single PWM mode period is T = 1.024*P [ms], where P is the number, written in bits 15…9 PWMCTRL. Maximum period isthen 131.072 ms for single and 262.144 ms for extended. These values are typical and depend on the on-chip RC oscillator
absolute value. The duty cycle must be calculated instead of working only with the high time only in order to avoid errors
from the period absolute value deviations.
The address PWMCTRL consists of control bits for configuring the PWM/SDA pin as follows:
15 14 13 12 11 109PWM control bit meaning
0
0 - PWM extended mode
1 - PWM single mode
0 - PWM mode disabled (EN_PWM)
1 - PWM mode enabled (EN_PWM)
0 - SDA pin configured as Open Drain (PPODB)
1 - SDA pin configured as Push-Pull (PPODB)
0 - PWM mode selected (TRPWMB)
1 - Thermal relay mode selected (TRPWMB)- PWM repetition number 0…62 step 2- PWM period 1.024*ms (Single PWM mode) or 2.048*ms (Extendet PWM mode)
multiplied by the number written in this place (128 in case the number is 0)
8

7

6

5

4

3

2

1

Table 6: PWM control bits
* Values are valid for nominal HFO frequency
The address ConfigRegister1 consists of control bits for configuring the analog and digital parts:
15 14 13 12 11 1098

Config register bit meaning
2
1 0
1
0 0 - IIR (100%) a1=1, b1=01
0 1 - IIR (80%) a1=0.8, b1=0.2
1
1 0 - IIR (67%) a1=0.666, b1=0.333
1
1 1 - IIR (57%) a1=0.571, b1=0.428
00 0 - IIR (50%) a1=0.5, b1=0.5
0
0 1 - IIR (25%) a1=0.25, b1=0.75
01 0 - IIR (17%) a1=0.166(6), b1=0.83(3)0
1 1 - IIR (13%) a1=0.125, b1=0.875
0 - Repeat sensor test "OFF"1 - Repeat sensor test "ON"00 - Ta, Tobj1
0
1 - Ta, Tobj2
1
0 - Tobj2
1
1 - Tobj1, Tobj2
0 - Single IR sensor
1 - Dual IR sensor
0 - Positive sign of Ks
7

6

5

4

3

1 - Negative sign of Ks
0 0 0 - FIR = 8 not recommended
0 0 1 - FIR = 16 not recommended
0 1 0 - FIR = 32 not recommended
0 1 1 - FIR = 64 not recommended
1 0 0 - FIR = 128
1 0 1 - FIR = 256
1 1 0 - FIR = 512
1 1 1 - FIR = 1024
0 0 0 - GAIN = 1 - Amplifier is bypassed
0 0 1 - GAIN = 3
0 1 0 - GAIN = 6
0 1 1 - GAIN = 12,5
1 0 0 - GAIN = 25
1 0 1 - GAIN = 50
1 1 0 - GAIN = 100
1 1 1 - GAIN = 100
0 - Positive sign of Kt2
1 - Negative sign of Kt2
0 - Enable sensor test
1 - Disable sensor test

Table 7: Configuration register 1
Note: The following bits / registers should not be altered (except with special tools – contact Melexis for such tools
availability) in order to keep the factory calibration relevant:Emissivity [15...0]; Config Register1 [14...11;7;3]; addresses 0x0F and 0x19.
Check www.melexis.com for latest application notes with details on EEPROM settings.

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On-chip filtering and settling time:
The MLX90614 features configurable on-chip digital filters. They allow customization for speed or noise. Factory default
configurations and the typical settling time and noise for the MLX90614 family are given below.
DeviceSettling time, sec
Typical noise, °C rms
Spike limit
MLX90614AAA, BAA, DAA
MLX90614ABA, BBA
MLX90614ACC, BCC, DCC
MLX90614ACF, BCF
MLX90614DCH, DCI, BCH, BCI
MLX90614ACK, BCK

0.10
0.14
0.14
1.33
0.65
3.23

0.05
0.07
0.18
0.10
0.10
0.30

100%
100%
100%
50%
80%
25%

Table 8: factory default IIR and FIR configuration, settling time and typical noise
Details on the filters are given in the application note “Understanding MLX90614 on-chip digital signal filters” available fromwww.melexis.com.
The evaluation board, EVB90614 supported by PC SW allows easy configuration of the filters, while not requiring in-depth
understanding of the EEPROM.
The available filter settings and the settling times are listed below. Settling time depends on three configurations: single /dual zone, IIR filter settings and FIR filter settings. The FIR filter has a straight forward effect on noise (4 times decreasing offilter strength increases the noise 2 times and vice versa). The IIR filter provides an additional, spike limiting feature. Spikelimit defines the level of magnitude to which the spike would be limited – for example, 25% denotes that if a 20°C
temperature delta spike is measured the temperature reading by the MLX90614 will spike only 5°C.
IIR setting

FIR setting

xxx
100
100
100
100
101
101
101
101
110
110
110
110
111
111
111
111
000
000
000
000
001
001
001
001
010
010
010
010
011
011
011
011

000…011
100
101
110
111
100
101
110
111
100
101
110
111
100
101
110
111
100
101
110
111
100
101
110
111
100
101
110
111
100
101
110
111

Settling time (s)90614xAx
0.04
0.05
0.06
0.10
0.12
0.16
0.22
0.35
0.24
0.30
0.43
0.70
0.26
0.34
0.48
0.78
0.30
0.37
0.54
0.86
0.70
0.88
1.30
2.00
1.10
1.40
2.00
3.30
1.50
1.90
2.80
4.50

Settling time (s)90614xBx, 90614xCx
Not recommended
0.06
0.07
0.10
0.14
0.20
0.24
0.34
0.54
0.38
0.48
0.67
1.10
0.42
0.53
0.75
1.20
0.47
0.60
0.84
1.33
1.10
1.40
2.00
3.20
1.80
2.20
3.20
5.00
2.40
3.00
4.30
7.00

Spike limit
100.00%100.00%100.00%100.00%80.00%
80.00%
80.00%
80.00%
66.70%
66.70%
66.70%
66.70%
57.00%
57.00%
57.00%
57.00%
50.00%
50.00%
50.00%
50.00%
25.00%
25.00%
25.00%
25.00%
16.70%
16.70%
16.70%
16.70%
12.50%
12.50%
12.50%
12.50%

Table 9: possible IIR and FIR settings
Note: Settling time is in seconds and depends on internal oscillator absolute value.
100% spike limit appears with the IIR filter bypassed, and there is no spike limitation.

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8.3.3.1. ERPROM write sequence
When EEPROM cell content is to be changed Melexis recommends following procedure:
1.
2.
3.
4.
5.
6.
7.

Power up the device
Write 0x0000 into the cell of interest (effectively erasing the cell)
Wait at least 5ms (10ms to be on the safe side)
Write the new value
Wait at least 5ms (10ms to be on the safe side)
Read back and compare if the write was successful
Power down (to be sure that when power up next time the changes will take place)

8.3.4. RAM
It is not possible to write into the RAM memory. It can only be read and only a limited number of RAM registers are ofinterest to the customer.
RAM (32x16)
AddressName
Melexis reserved…
Melexis reserved
Raw data IR channel 1
Raw data IR channel 2

TA

TOBJ1
TOBJ2
Melexis reserved…
Melexis reserved

Read access

0x00
…
0x03
0x04
0x05
0x06
0x07

Yes
…
Yes

Yes
Yes

0x08
0x09
…
0x1F

Yes
Yes
…
Yes

Table 10: Ram addresses

8.4. SMBus compatible 22-wire protocol
The chip supports a 2 wires serial protocol, build with pins PWM / SDA and SCL.
SCL – digital input only, used as the clock for SMBus compatible communication. This pin has the auxiliary
function for building an external voltage regulator. When the external voltage regulator is used, the 2-wireprotocol is available only if the power supply regulator is overdriven.
PWM/SDA – Digital input / output, used for both the PWM output of the measured object temperature(s) or
the digital input / output for the SMBus. In PWM mode the pin can be programmed in EEPROM to operate as
Push / Pull or open drain NMOS (open drain NMOS is factory default). In SMBus mode SDA is forced to open
drain NMOS I/O, push-pull selection bit defines PWM / Thermal relay operation.
SMBus communication with MLX90614 is covered in details in application notes, available from www.melexis.com.

8.4.1. Functional description
The SMBus interface is a 2-wire protocol, allowing communication between the Master Device (MD) and one or more Slave
Devices (SD). In the system only one master can be presented at any given time [1]. The MLX90614 can only be used as aslave device.
Generally, the MD initiates the start of data transfer by selecting a SD through the Slave Address (SA).
The MD has read access to the RAM and EEPROM and write access to 9 EEPROM cells (at addresses 0x00, 0x01, 0x02, 0x03,
0x04, 0x05*, 0x0E, 0x0F, 0x19). If the access to the MLX90614 is a read operation it will respond with 16 data bits and 8 bit
PEC only if its own slave address, programmed in internal EEPROM, is equal to the SA, sent by the master. The SA feature

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allows connecting up to 127 devices (SA=0x00…0x07F) with only 2 wires, unless the system has some of the specific featuresdescribed in paragraph 5.2 of reference [1]. In order to provide access to any device or to assign an address to a SD before it
is connected to the bus system, the communication must start with zero SA followed by low R/W̄ bit. When this command issent from the MD, the MLX90614 will always respond and will ignore the internal chip code information.
Special care must be taken not to put two MLX90614 devices with the same SA on the same bus as MLX90614 does notsupport ARP [1].
The MD can force the MLX90614 into low consumption mode “sleep mode” (3V version only).
Read flags like “EEBUSY” (1 – EEPROM is busy with executing the previous write/erase), “EE_DEAD” (1 – there is fatal
EEPROM error and this chip is not functional**).
Note*: This address is readable and writable. Bit 3 should not be altered as this will cancel the factory calibration.
Note**: EEPROM error signaling is implemented in automotive grade parts only.

8.4.2. Differences with the standard SMBus specification (reference [1])There are eleven command protocols for standard SMBus interface. The MLX90614 supports only two of them. Not
supported commands are:
Quick Command
Byte commands - Sent Byte, Receive Byte, Write Byte and Read Byte
Process Call
Block commands – Block Write and Write-Block Read Process Call
Supported commands are:Read Word
Write Word

8.4.3. Detailed description
The PWM / SDA pin of MLX90614 can operate also as PWM output, depending on the EEPROM settings. If PWM is enabled,
after POR the PWM / SDA pin is directly configured as PWM output. Even if the device is in PWM mode SMBus
communication may be restored by a special command. That is why hereafter both modes are treated separately.

8.4.3.1. Bus Protocol
1

7

1

S

Slave Address

1

Wr A

8

1

1

Data Byte

A

PS

Start Condition

Sr

Repeated Start Condition

Rd

Read (bit value of 1)

Wr

Write (bit value of 0)A

Acknowledge (this bit can be 0 for ACK and 1 for NACK)S

Stop Condition

PEC

Packet Error Code
Master-to-Slave
Slave-to-MasterFigure 4: SMBus packet element key

After every received 8 bits the SD should issue ACK or NACK. When a MD initiates communication, it first sends the addressof the slave and only the SD which recognizes the address will ACK, the rest will remain silent. In case the SD NACKs one of
the bytes, the MD should stop the communication and repeat the message. A NACK could be received after the PEC. ThisREVISION 13 - 13 SEPTEMBER 2019
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means that there is an error in the received message and the MD should try sending the message again. The PEC calculation
includes all bits except the START, REPEATED START, STOP, ACK, and NACK bits. The PEC is a CRC-8 with polynomial
X8+X2+X1+1. The Most Significant Bit of every byte is transferred first.
8.4.3.1.1. Read Word (depending on the command – RAM or EEPROM)
1
S

7

1

Slave Address

………..

1

Wr A

8

1

1

7

1

1

CommandA

Sr

Slave Address

Rd

A

8

1

8

1

8

1

1

Data Byte Low

A

Data Byte High

A

PEC

A

P

………..

Figure 5: SMBus read word format
8.4.3.1.2. Write Word (depending on the command – RAM or EEPROM)
1

………..

7

1

1

8

1

Wr A

Command

A

………..

S

Slave Address

8

1

8

1

8

1

1

Data Byte Low

A

Data Byte High

A

PEC

A

P

Figure 6: SMBus write word format

8.4.4. Bit transfer
Changing data

SDA

SCL

Sampling data

Figure 7: Recommended timing on SMBus

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The data on PWM / SDA must be changed when SCL is low (min 300ns after the falling edge of SCL). The data is fetched byboth MD and SDs on the rising edge of the SCL. The recommended timing for changing data is in the middle of the period
when the SCL is low.

8.4.5. Commands
RAM and EEPROM can be read both with 32x16 sizes. If the RAM is read, the data are divided by two, due to a sign bit in
RAM (for example, TO1 - RAM address 0x07 will sweep between 0x27AD to 0x7FFF as the object temperature changes from 70.01°C…+382.19°C). The MSB read from RAM is an error flag (active high) for the linearized temperatures (TO1, TO2 and Ta).
The MSB for the raw data (e.g. IR sensor1 data) is a sign bit (sign and magnitude format). A write of 0x0000 must be done
prior to writing in EEPROM in order to erase the EEPROM cell content. Refer to EEPROM detailed description for factory
calibration EEPROM locations that need to be kept unaltered.

Opcode000x xxxx*
001x xxxx*
1111_0000**
1111_1111

Command
RAM Access
EEPROM Access
Read Flags
Enter SLEEP mode

Table 11: SMBus commands
Note*: The xxxxx represent the 5 LSBits of the memory map address to be read / written.
Note**: Behaves like read command. The MLX90614 returns PEC after 16 bits data of which only 4 are meaningful and if the
MD wants it, it can stop the communication after the first byte. The difference between read and read flags is that the latterdoes not have a repeated start bit.
Flags read are:Data[7] - EEBUSY - the previous write/erase EEPROM access is still in progress. High active.
Data[6] - Unused
Data[5] - EE_DEAD - EEPROM double error has occurred. High active.
Data[4] - INIT - POR initialization routine is still ongoing. Low active.
Data[3] - Not implemented.
Data[2...0] and Data[8...15] - All zeros.
Flag read is a diagnostic feature. The MLX90614 can be used regardless of these flags.

For details and examples for SMBus communication with the MLX90614 check the www.melexis.com

8.4.6. SMBus communication examples
SA_W = 0xB4

Command = 0x07

SA_R = 0xB5

LSByte = 0xD2

MSByte = 0x3A

PEC = 0x30

SDA
S 1 0 1 1 0 1 0

W A 0 0 0 0 0 1 1 1 A

S 1 0 1 1 0 1 0 R A 1 1 0 1 0 0 1 0 A 0 0 1 1 1 0 1

0 A 0 0 1 1 0 0 0

0 A

P

SCL

Figure 8: Read word format (SA=0x5A, read RAM=0x07, result=0x3AD2, PEC=0x30)

SA_W = 0xB4

Command = 0x22

LSByte = 0x07

MSByte = 0xC8

PEC = 0x48

SDA
S 1 0 1 1 0 1 0

W A 0

0 1 0 0 0 1 0 A 0 0 0 0 0 1 1

1 A 1 1 0 0 1 0 0

0 A 0 1 0 0 1 0 0 0 A

P

SCL

Figure 9: Write word format (SA=0x5A, write EEPROM=0x02, data=0xC807, PEC=0x48)

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8.4.7. Timing specification
The MLX90614 meets all the timing specifications of the SMBus [1]. The maximum frequency of the MLX90614 SMBus is 100
KHz and the minimum is 10 KHz.
The specific timings in MLX90614’s SMBus are:
SMBus Request (tREQ ) is the time that the SCL should be forced low in order to switch MLX90614 from PWM mode to SMBus
mode – at least 1.44ms;
Timeout L is the maximum allowed time for SCL to be low during communication. After this time the MLX90614 will reset its
communication block and will be ready for new communication – not more than 27ms;
Timeout H is the maximum allowed time for SCL to be high during communication. After this time MLX90614 will reset its
communication block assuming that the bus is idle (according to the SMBus specification) – not more than 45μs.
Tsuac(SD) is the time after the eighth falling edge of SCL that MLX90614 will force PWM / SDA low to acknowledge the lastreceived byte – not more than 2.5μs.
Thdac(SD) is the time after the ninth falling edge of SCL that MLX90614 will release the PWM / SDA (so the MD can continue
with the communication) – not more than 1.5μs.
Tsuac(MD) is the time after the eighth falling edge of SCL that MLX90614 will release PWM / SDA (so that the MD can
acknowledge the last received byte) – not more than 1,5μs.
Thdac(MD) is the time after the ninth falling edge of SCL that MLX90614 will take control of the PWM / SDA (so it cancontinue with the next byte to transmit) – not more than 1.5μs.
The indexes MD and SD for the latest timings are used – MD when the master device is making acknowledge; SD when theslave device is making acknowledge. For other timings see [1].
Tsuac

Thdac

SDA
1
SCL

0
1

1
2

0
3

1
4

0
5

1
6

1
7

> 27ms> 45µsTimeout_L

Timeout_H

ACK
8

MD < 1.5µs
SD < 2.5µs

9MD < 1.5µs
SD < 1.5µs

Figure 10: SMBus timing specification and definition

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8.4.8. Sleep Mode
The MLX90614 can enter in Sleep Mode via the command “Enter SLEEP mode” sent via the SMBus interface. This mode is
not available for the 5V supply version. There are two ways to put MLX90614 into power-up default mode:- POR- By Wake up request SCL pin high and then PWM/SDA pin low for at least tDDQ > 33ms
If EEPROM is configured for PWM (EN_PWM is high), the PWM interface will be selected after awakening and if PWM
control [2], PPODB is 1 the MLX90614 will output a PWM pulse train with push-pull output.
NOTE: In order to limit the current consumption to the typical 2.5μA Melexis recommends that the SCL pin is kept low during
sleep as there is leakage current trough the internal synthesized zener diode connected to SCL pin. This may be achieved byconfiguring the MD driver of SCL pin as Push-Pull and not having Pull-Up resistor connected on SCL line.

8.4.8.1. Enter Sleep Mode
Normal operation mode
SA_W = 0xB4

Command = 0xFF

0 1 1 0 1 0 W A 1

1 1 1 1 1 1 1 A 1 1 1 0 1 0 0

Sleep mode

PEC = 0xE8

SDA
S 1

0 A

P

SCL

Figure 11: Enter sleep mode command (SA = 0x5A, Command = 0xFF, PEC = 0xE8)

8.4.8.2. Exit from Sleep Mode (Wake up request)
Sleep mode

Normal mode

SDA

SCL

> 33msFigure 12: Exit Sleep Mode
After wake up the first data is available after 0.25 seconds (typ). On-chip IIR filter is skipped for the very first measurement.
All measurements afterwards pass the embedded digital filtering as configured in EEPROM. Details on embedded filtering
are available in application note “Understanding MLX90614 on-chip digital signal filters”, available from www.melexis.com

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8.4.9. MLX90614 SMBus specific remarks
The auxiliary functions of the SCL pin (zener diode) add undershoot to the clock pulse (5V devices only) as shown in the
picture below (see Figure 13). This undershoot is caused by the transient response of the on-chip synthesized Zener diode.
Typical duration of undershoot is approximately 15μs. An increased reactance of the SCL line is likely to increase this effect.
Undershoot does not affect the recognition of the SCL rising edge by the MLX90914, but may affect proper operation of nonMLX90614 slaves on the same bus.

Figure 13: Undershoot of SCL line due to on chip synthesized Zener diode (5V versions only)
Continuous SMBus readings can introduce and error. As the SCL line inside TO39 package is passing relatively close to thesensor input and error signal is induced to the sensor output. The manifestation of the problem is wrong temperature
readings. This is especially valid for narrow FOV devices. Possible solution is to keep SDA and SCL line quiet for period longer
than refresh rate and settling time defined by internal settings of MLX90614 prior reading the temperature or switch to
PWM signal and completely disconnect from SDA and SCL line.

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8.5. PWM
The MLX90614 can be read via PWM or SMBus compatible interface. Selection of PWM output is done in EEPROM
configuration (factory default is SMBus). PWM output has two programmable formats, single and dual data transmission,
providing single wire reading of two temperatures (dual zone object or object and ambient). The PWM period is derived
from the on-chip oscillator and is programmable.
Config Register[5:4]
00
01
11

PWM1 data
TA
TA
TO1

PWM2 data
TO1
TO2
TO2

10*

T O2

Undefined

Tmin,1
TA_range,LTA_range,L
TO_MIN
TO_MIN

Tmax,1
TA_range,H
TA_range,H
TO_MAX
TO_MAX

Tmin,2
TO_MIN
TO_MIN
TO_MIN
N.A.

Tmax,2
TO_MAX
TO_MAX
TO_MAX
N.A.

Table 12: PWM configuration table
Note: Serial data functions (2-wire / PWM) are multiplexed with a thermal relay function (described in the “Thermal
relay” section).
* Not recommended for extended PWM format operationt3

FE

Error band

Start

Valid data band

Stop

t1

t2

t4

1 T
8

0

5 T
8

13 T
16

0

Valid data band
Sensor 1

t1

t2

1 T
16

t7
Error band
Sensor 2
Valid data band
Sensor 2

Stop
t4

5 T
16

T

t5

FE

Start

FE

t3
Error band
Sensor 1

7 T
8

t6

7 T 8 T 9 T
16
16
16

t8

13 T
16

15 T
16

T

Figure 14: PWM timing single (above) and extended PWM (bellow)
PWM type

t1

t2

t3

t4

t5

t6

t7

t8

Single

1/8 – high

4/8 - var

2/8

1/8 – low

NA

NA

NA

NA

Extended - S1

1/16 - high

4/16 - var

2/16

1/16 - low

1/16 - low

4/16 – low

2/16 - low

1/16 - low

Extended - S2

1/16 - high

4/16 - high

2/16 - high

1/16 - high

1/16 - high

4/16 - var

2/16

1/16 - low

Table 13: PWM timing

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MLX90614 family
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Infra Red Thermometer in TO-39

8.5.1. Single PWM format
In single PWM output mode the settings for PWM1 data only are used. The temperature reading can be calculated from thesignal timing as: 2tTOUT =  2 × (TO _ MAX − TO _ MIN ) + TO _ MIN T
where Tmin and Tmax are the corresponding rescale coefficients in EEPROM for the selected temperature output (Ta, object
temperature range is valid for both Tobj1 and Tobj2 as specified in the previous table) and T is the PWM period. Tout is TO1,TO2 or Ta according to Config Register [5:4] settings.
The different time intervals t1…t4 have following meaning:t1: Start buffer. During this time the signal is always high. t1 = 0.125s x T (where T is the PWM period, please refer toFigure 14).
t2: Valid Data Output Band, 0…1/2T. PWM output data resolution is 10 bit.
t3: Error band – information for fatal error in EEPROM (double error detected, not correctable).
t3 = 0.25s x T. Therefore a PWM pulse train with a duty cycle of 0.875 will indicate a fatal error in EEPROM (for single PWM
format). FE means Fatal Error.
Example:Figure 15: PWM example single mode

TO _ MIN = 0°C

TO _ MIN (EEPROM ,0 x01) = 100 × (TO _ MIN + 273.15) = 27315d = 0 x6 AB3

TO _ MAX = 50°C

TO _ MAX (EEPROM ,0 x00 ) = 100 × (TO _ MAX + 273.15) = 32315d = 0 x7 E 3B

Captured PWM period is T = 1004μs
Captured high duration is t = 392 μs
Calculated duty cycle is:

D=

t
392
=
= 0.3904 or 39.04%
T 1004

The temperature is calculated as follows:

TO = 2 × (0.3904 − 0.125) × (50 − 0) + 0 = 2 × 0.2654 × 50 = 26.54°C

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MLX90614 family
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8.5.2. Extended PWM format
The PWM format for extended PWM is shown in Figure 16. Note that with bits DUAL[5:1]>0x00 each period will be
outputted 2N+1 times, where N is the decimal value of the number written in DUAL[5:1] (DUAL[5:1] =PWM control &clock [8:4] ), like shown on Figure 16.

Figure 16: Extended PWM format with DUAL [5:1] = 01h (2 repetitions for each data)
The temperature transmitted in Data 1 field can be calculated using the following equation:

 4t
TOUT 1 =  2 × (TMAX 1 − TMIN 1 ) + TMIN 1
 T

For Data 2 field the equation is: 4tTOUT 2 =  5 × (TMAX 2 − TMIN 2 ) + TMIN 2 T
Time bands are: t1=0.0625 x T (Start1), t3=0.125 x T and t4=0.5625 x T (Start2 = Start1 + Valida_data1 + error_band1 + stop1 +start2). As shown in Figure 13, in extended PWM format the period is twice the period for the single PWM format. All
equations provided herein are given for the single PWM period T. The EEPROM Error band signaling will be 43.75% duty
cycle for Data1 and 93.75% for Data2.
Note: EEPROM error signaling is implemented in automotive grade parts only.

T=100ms (PWM = 10Hz)
t=16.875ms
Start
t1

0

Extended PWM mode sensor 1

t2

1 T
16

8 T
16

15 T
16

T

15 T
16

T

T=100ms (PWM = 10Hz)
t=73.125ms
Start

Extended PWM mode sensor 2
t1

0

1 T
16

t2

8 T
16

t3

Figure 17: Example: Extended PWM mode readings – sensor 1 above and sensor 2 bellow

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MLX90614 family
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Infra Red Thermometer in TO-39
Example: (see Figure 17 above):
Configuration:
Sensor1 = Ta, Sensor2 = Tobj1

TA _ MIN = 0°C
TA _ MAX = 60°C

Config Reg[5:4] = 00b,

TA _ RANGE _ L (EEPROM ) = 100 ×(T

TA _ RANGE _ H (EEPROM ) = 100 ×A _ min(T+ 38.2)64

A _ max= 59.6875 ≈ 60d = 0 x3C+ 38.2)64= 153.4375 ≈ 153d = 0 x99

TA _ RANGE (EEPROM ,0 x03) = {TA _ RANGE _ H : TA _ RANGE _ L } = 0 x993C

TO _ MIN = 0°C

TO _ MIN (EEPROM ,0 x01) = 100 × (TO _ min + 273.15) = 27315d = 0 x6 AB3

TO _ MAX = 50°C

TO _ MAX (EEPROM ,0 x00 ) = 100 × (TO _ min + 273.15) = 32315d = 0 x7 E 3B

Captured high durations are:Sensor 1 – t = 16.875ms at period T = 100ms thus the duty cycle is Duty S 1 =16.875= 0.16875
100

Sensor 2 – t = 73.125ms at period T = 100ms thus the duty cycle is Duty S 2 =73.125= 0.73125
100

The temperatures are calculated as follows:

TA = 4 × (DutyS 1 − Start1) × (TA _ MAX − TA _ MIN ) + TA _ MIN
TA = 4 × (0.16875 − 0.0625) × (60 − 0) + 0 = 25.5°C

TO1 = 4 × (DutyS 2 − Start 2 ) × (TO _ MAX − TO _ MIN ) + TO _ MIN
TO1 = 4 × (0.73125 − 0.5625) × (50 − 0 ) + 0 = 33.75°C

8.5.3. Customizing the temperature range for PWM output
The calculated ambient and object temperatures are stored in RAM with a resolution of 0.01°C (16 bit). The PWM operates
with a 10-bit word so the transmitted temperature is rescaled in order to fit in the desired range.
For this goal 2 cells in EEPROM are foreseen to store the desired range for To (Tomin and Tomax) and one for Ta (Tarange: the8MSB are foreseen for Tamax and the 8LSB for Tamin).
Thus the output range for To can be programmed with an accuracy of 0.01°C, while the corresponding Ta range can be
programmed with an accuracy of 0.64°C.
The object data for PWM is rescaled according to the following equation:

TPWM obj =TRAM − TMIN EEPROM
K PWM obj

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MLX90614 family
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The TRAM is the linearized Tobj, 16-bit (0x0000…0xFFFF, 0x0000 for -273.15°C and 0xFFFF for +382.2°C) and the result is a 10bit word, in which 0x000 corresponds to ToMIN ,°C, 0x3FF corresponds to ToMAX,°C and 1LSB corresponds to

ToMAX − ToMIN
1023

,°C.

TMIN EEPORM = TMIN × 100 LSB
TMAX EEPORM = TMAX × 100 LSB
The ambient data for PWM is rescaled according to the following equation:

TPWM ambient =TRAM − TMIN EEPROM
K PWM ambient

Where:K PWM ambient =TMAX EEPROM − TMIN EEPROM
1023

The result is a 10-bit word, where 0x000 corresponds to -38.2°C (lowest Ta that can be read via PWM), 0x3FF corresponds to
125°C (highest Ta that can be read via PWM) and 1LSB corresponds to:

1LSB =

TMAX − TMIN
, [°C ]
1023

TMIN EEPORM = (TMIN − (− 38.2)) ×

100
LSB
64

TMAX EEPORM = (TMAX − (− 38.2)) ×

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100
LSB
64

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MLX90614 family
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Infra Red Thermometer in TO-39

8.6. Switching Between PWM / Thermal relay and SMBus communication
8.6.1. PWM is enabled
The diagram below illustrates the way of switching to SMBus if PWM / Thermal Relay is enabled (factory programmed POR
default for MLX90614 is SMBus, PWM disabled). Note that the SCL pin needs to be kept high in order to use PWM.

tREQ>1.44ms
SCL

PWM/SDAStart

PWM mode

SMBus mode

Stop

Figure 18: Switching from PWM mode to SMBus

8.6.2. Request condition
tREQ >1,44ms
SCL

SMBus Request
Figure 19: Request (switch to SMBus) condition
If PWM / Thermal relay is enabled, the MLX90614’s SMBus Request condition is needed to disable PWM / Thermal relay andreconfigure PWM/SDA pin before starting SMBus communication. Once PWM / Thermal relay is disabled, it can be only
enabled by switching the supply OFF – ON or exit from Sleep Mode. The MLX90614’s SMBus request condition requires
forcing LOW the SCL pin for period longer than the request time (tREQ >1,44ms). The SDA line value is ignored and isirrelevant in this case.

8.6.3. PWM is disabled
If PWM is disabled by means of EEPROM the PWM / SDA pin is directly used for the SMBus after POR. Request condition
should not be sent in this case.

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8.7. Computation of ambient and object temperatures
The IR sensor consists of serial connected thermo-couples with cold junctions placed at thick chip substrate and hot
junctions, placed over thin membrane. The IR radiation absorbed from the membrane heats (or cools) it. The thermopile
output signal is:(

Vir (Ta, To ) = A × To 4 − Ta 4)

Where To is the absolute object temperature (Kelvin), Ta is the sensor die absolute (Kelvin) temperature, and A is the overallsensitivity.
An on board temperature sensor is needed to measure the chip temperature. After measurement of the output of both
sensors, the corresponding ambient and object temperatures can be calculated. These calculations are done by the internal
DSP, which produces digital outputs, linearly proportional to measured temperatures.

8.7.1. Ambient temperature Ta
The Sensor die temperature is measured with a PTAT element. All the sensors conditioning and data processing is handled
on-chip and the linearized sensor die temperature Ta is available in memory.
The resolution of the calculated temperature is 0.02°C. The sensor is factory calibrated for the full automotive
range -40…+125°C. The linearized die temperature is available in RAM cell 0x06:
0x06=0x2DE4 (11748d) corresponds to -38.2°C (linearization output lower limit)
0x06=0x4DC4 (19908d) corresponds to +125°C. (linearization output higher limit)
The conversions from RAM contend to real Ta is easy using the following relation:

Ta[° K ] = Tareg × 0.02 , or 0.02°K / LSB.

8.7.2. Object temperature To
The result has a resolution of 0.02°C and is available in RAM. To is derived from RAM as:

To[° K ] = Toreg × 0.02 , or 0.02°K / LSB.
Please note that 1LSB corresponds to 0.02°C and the MSB bit is error flag (if “1” then error).
Example:1. 0x27AD
2. 0x27AE
3. 0x3AF7
4. 0x3AF8
5. 0x7FFF
6. 0x8XXX-70.00˚C (no error)-69.98˚C (no error)
28.75˚C (no error)
28.77˚C (no error)
382.19˚C (no error) - maximum possible value returned by MLX90614
xxx.xx˚C (flag error)

The result is calculated by following expressions (valid for both To and Ta):
1. Convert it to decimal value i.e. 0x3AF7 = 15095d

2. Divide by 50 (or multiply by 0.02) i.e.

15095
= 301.9 K (result is in Kelvin)50

3. Convert K -> °C i.e. 301.9 - 273.15 = 28.75°C

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8.7.3. Calculation flow
The measurement, calculation and linearization are held by core, which executes a program form ROM.
After POR the chip is initialized with calibration data from EEPROM. During this phase the number of IR sensors is selected
and it is decided which temperature sensor will be used. Measurements, compensation and linearization routines run in aclosed loop afterwards.
Processing ambient temperature includes:
Offset measurement with fixed length FIR filter
Additional filtering with fixed length IIR filter. The result is stored into RAM as TOS
Temperature sensor measurement using programmable length FIR *.
Offset compensation
Additional processing with programmable length IIR **. The result is stored into RAM as TD.
Calculation of the ambient temperature. The result is stored into RAM address 0x06 as TA
Processing of the object temperature consists of three parts.
The first one is common for both IR sensors, the third part can be skipped if only one IR sensor is used.
IR offset:
Offset measurement with a fixed length FIR
Additional filtering with a fixed length IIR. The result is stored into RAM as IROS.
Gain measurement with fixed length FIR filter
Offset compensation
Additional gain filtering with fixed length IIR, storing the result into RAM as IRG.
Gain compensation calculation, the result is stored into RAM as KG
Object temperature:
IR1 sensor:
IR sensor measurement with programmable length FIR filter *.
Offset compensation
Gain compensation
Filtering with programmable length IIR filter**, storing the result into RAM address 0x04 as IR1D.
Calculation of the object temperature. The result is available in RAM address 0x07 as TO1.
IR2 sensor:
IR sensor measurement with programmable length FIR filter *.
Offset compensation
Gain compensation
Filtering with programmable length IIR filter**, storing the result into RAM address 0x05 as IR2D
Calculation of the object temperature. The result is available in RAM address 0x08 as TO2
PWM calculation:
Recalculate the data for PWM with 10 bit resolution
Load data into PWM module
Note*: The measurements with programmable filter length for FIR filter use the same EEPROM cells for N.
Note**: The IIR filter with programmable filter length uses the same EEPROM cells for L.

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MLX90614 family

3

TA Offset meas
OSTa= meas(NTos)

IR Offset meas
OSIR= meas(NIRos)

IR1 meas
IR1D= meas(NIR)

IR2 meas
IR2D= meas(NIR)

filtering
TOS= IIR(LTos,OSTa)

filtering
IROS= IIR(LIRos,OSIR)

Offset compIR1Dcomp= IR1D- IROS

Offset compIR2Dcomp= IR2D- IROS

TA measTDATA= meas(NTa)Gain drift
IRGm= meas(NIRg)

Gain compIR1Dg= IR1Dcomp*KG

Gain compIR2Dg= IR2Dcomp*KG

Offset comp
TDATAcomp= TDATA-TOS

Offset comp
IRGcomp= IRGm- IROS

filtering
IR1D= IIR(LIR,IR1Dg)

filtering
IR2D= IIR(LIR,IR2Dg)

filtering
TD= IIR(LTa,TDATAcomp)filtering
IRG= IIR(LG,IRGcomp)TOBJ1 calculation

TA calculation

KG calculationTA

TOBJ2 calculation
PWM calculation
Load PWM registers

3

2

1

TOBJ1

2

IR offset

1

Initialization

TOBJ2Single and Dual Zone
Infra Red Thermometer in TO-39

Figure 20: Software flow

8.8. Thermal relay
The MLX90614 can be configured as a thermo relay with programmable threshold and hysteresis on the PWM/SDA pin. The
input for the comparator unit of the relay is the object temperature from sensor 1
The output of the MLX90614 is NOT a relay driver but a logical output which should be connected to a relay driver ifnecessary.
The output driver is one and the same for PWM and Thermal relay.
In order to configure the MLX90614 to work as thermal relay two conditions must be met:o Set bit TRPWMB high at address 0x02 in EEPROM
o Enable PWM output i.e. EN_PWM is set high
The PWM / SDA pin can be programmed as a push-pull or open drain NMOS (via bit PPODB in EEPROM PWMCTRL), which
can trigger an external device. The temperature threshold data is determined by EEPROM at address 0x21 (Tomin) and thehysteresis at address 0x020 (Tomax).
The logical state of the PWM/SDA pin is as follows:
PWM / SDA pin is high if TO1 ≥ threshold + hysteresis
PWM / SDA pin is low if TO1 ≤ threshold − hysteresis“1”hysteresis

hysteresis“0”
thresholdT

Figure 21: Thermal relay: “PWM” pin versus Tobj

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MLX90614 family
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The MLX90614 preserves its normal operation when configured as a thermal relay (PWM configuration and specification
applies as a general rule also for the thermal relay) and therefore it can be read using the SMBus (entering the SMBus mode
from both PWM and thermal relay configuration is the same).
For example, the MLX90614 can generate a wake-up alert for a system upon reaching a certain temperature and then beread as a thermometer. Reset conditions (enter and exit Sleep, for example) will be needed in order to return to the thermal
relay configuration.
Example:Threshold = 5°C(EEPROM ,0 x01) = 100 × (Threshold + 273.15) = 27815d = 0 x6CA7

Hysteresis = 1°C(EEPROM ,0 x00) = 100 × Hysteresis = 100d = 0 x0064

Smallest possible hysteresis is 0,01°C or (EEPROM, 0x00 = 0x0001)
PWM / SDA pin will be set low at object temperature below 4°C
PWM / SDA pin will be set high at object temperature higher that 6°C

9. Unique Features
The MLX90614 is a ready-to use low-cost non-contact thermometer provided from Melexis with output datalinearly dependent on the object temperature with high accuracy and extended resolution.
The high thermal stability of the MLX90614-xCx make this part highly suited in applications where secondary
heat sources can heat up the sensor. These sensors also have a very short stabilization time compared toother types of thermopile sensors, which is of importance if one needs an accurate measurement in conditions
where the ambient temperature can change quickly.
The MLX90614 supports versatile customization to a very wide range of temperatures, power supplies andrefresh rates.
The user can program the internal object emissivity correction for objects with a low emissivity. An embedded
error checking and correction mechanism provides high memory reliability.
The sensors are housed in an industry standard TO39 package for both single- and dual-zone IR thermometers.
The thermometer is available in automotive grade and can use two different packages for wider applications’coverage.
The low power consumption during operation and the low current draw during sleep mode make thethermometer ideally suited for handheld mobile applications.
The digital sensor interface can be either a power-up-and-measure PWM or an enhanced access SMBus
compatible protocol. Systems with more than 100 devices can be built with only two signal lines. Dual zone
non-contact temperature measurements are available via a single line (extended PWM).
A build-in thermal relay function further extends the easy implementation of wide variety of freezing/boilingprevention and alert systems, as well as thermostats (no MCU is needed).

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MLX90614 family
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Infra Red Thermometer in TO-39

10. Performance Graphs
10.1. Temperature accuracy of the MLX90614
10.1.1. Standard accuracy
To, °C
380

±4°C
300
±4°C

240

±3°C

180

±4°C

±3°C

±2°C

±2°C

±2°C

±3°C

±2°C

±1°C

±1°C

±2°C

±2°C

±1°C

±0.5°C

±1°C

±2°C

120

60

0
Ta, °C
±3°C

±1°C

±1°C

±2°C

±3°C

±3°C

±3°C

±2°C

±3°C

±4°C

-40

-70
-40

0

-20

50

100

125

Figure 22: Accuracy of MLX90614 (Ta, To) except for xCK type

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
To, °C
380

±10°C

300
±10°C

240
±4°C

180

±10°C

±4°C

±3°C

±3°C

±3°C

±4°C

±2.5°C

±2°C

±2°C

±3°C

±3°C

±2°C

±0.75°C

±2°C

±3°C

120

60

0
Ta, °C
±4°C

±2°C

±2°C

±2.5°C

±4°C

±4°C

±4°C

±3°C

±4°C

±10°C

-40

-70
-40

-20

0

50

100

125

Figure 23 Accuracy of MLX90614xCK (Ta, To) only
All accuracy specifications apply under settled isothermal co23nditions only. Furthermore, the accuracy is only valid if theobject fills the FOV of the sensor completely.

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MLX90614 family
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Infra Red Thermometer in TO-39

10.1.2. Medical accuracy
A version of the MLX90614 with accuracy suited for medical applications is available. The accuracy in the range
Ta 16°C…40°C and To 22°C…40°C is shown in diagram below. The accuracy for the rest of the temperature ranges is the sameas in previous diagram. Medical accuracy specification is only available for the MLX90614Dxx versions.

To, °C40
38± 0.3°C± 0.2°C

3630± 0.3°C

22
20

Ta, °C
10

20

30

40

Figure 24: Accuracy of MLX90614DAA (Ta, To) for medical applications.
Accuracy of the MLX90614DCC, DCH and DCI for VDD = 3V (see paragraph 10.1.3)
Versions MLX90614ESF-DCC, -DCH and -DCI comply with ASTM standard section 5.4 (Designation: E1965 – 98 (Re-approved2009) - Standard Specification for Infrared Thermometers for Intermittent Determination of Patient Temperature
It is very important for the application designer to understand that the accuracy specified in Figure 22 and Figure 24 are only
guaranteed when the sensor is in thermal equilibrium and under isothermal conditions (there are no temperature
differences across the sensor package). The accuracy of the thermometer can be influenced by temperature differences in
the package induced by causes like (among others): Hot electronics (heaters / coolers) behind or beside the sensor or whenthe measured object is so close to the sensor that heats the thermometer package.
This effect is especially relevant for thermometers with a small Field Of View (FOV) like the xxC and xxF as the energy
received by the sensor from the object is reduced. Therefore, Melexis has introduced the xCx version of the MLX90614. In
these MLX90614xCx, the thermal gradients are measured internally and the measured temperature is compensated forthem. In this way, the MLX90614xCx is much less sensitive to thermal gradients induced from outside, but the effect is nottotally eliminated. It is therefore important to avoid introducing strong heat sources close to the sensor or to shield thesensor from them.
NOTE: In order to have the highest possible signal and the best performance a higher gain of the amplifier is selected for
MLX90614DCx type of devices. This eventually would limit the maximum object temperature (due to overload of the ADC) toabout 200°C.

10.1.3. Temperature reading dependence on VDD
In case of medical applications where high accuracy is required and the supply is provided by means of a battery, acompensation of temperature readings from VDD dependence should be done by the microcontroller. The dependence isvery repeatable and compensation can easily be implemented. As this dependence comes from the ambient temperature itis the same for all type of devices regardless of FOV and optics used and it directly translates in the same compensation for
object temperature.
The typical VDD dependence of the ambient and object temperature is 0.6°C/V.

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Infra Red Thermometer in TO-39
Typical Ta=f(VDD) dependance
0.50

Sensor1
Sensor2

0.40

Ta error, DegC

Sensor3
0.30

Sensor4

0.20

Sensor5
Sensor6

0.10

Sensor7

0.00
-0.10

Sensor8
2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

Sensor9
Sensor10-0.20

Sensor11-0.30

Sensor12
Sensor13-0.40

Sensor14-0.50

Sensor15
VDD, V

Sensor16

Figure 25: Typical Ta dependence from supply voltage
Example: As the devices are calibrated at VDD=3V the error at VDD=3V is smallest one. The error in ambient channel isdirectly transferred as object channel error (see Figure 26 below).
Typical To=f(VDD) dependance
0.50

Sensor1
Sensor2

0.40

To error, DegC

Sensor3
0.30

Sensor4

0.20

Sensor5
Sensor6

0.10

Sensor7

0.00
-0.10

Sensor8
2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

Sensor9
Sensor10-0.20

Sensor11-0.30

Sensor12
Sensor13-0.40

Sensor14-0.50

Sensor15
VDD, V

Sensor16

Figure 26: Typical To dependence from supply voltage (practically the same as Ta dependence error
In order to compensate for this error we measure supply voltage and by applying following equation compensate the result.

TO _ compensated = TO − (VDD − VDD0 ) × Typical _ dependence = TO − (VDD − 3) × 0.6
Compensated VDD dependence
Sensor1

0.5

To_compensated error, degC

Sensor2
0.4

Sensor3

0.3

Sensor4
Sensor5

0.2

Sensor6

0.1

Sensor7
Sensor8

0
-0.1

2.2

2.4

2.6

2.8

3

3.2

3.4

3.6

3.8

Sensor9
Sensor10
Sensor11-0.2

Sensor12-0.3

Sensor13-0.4

Sensor14
Sensor15-0.5
VDD, V

Sensor16

Figure 27: Typical To compensated dependence error

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MLX90614 family
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Infra Red Thermometer in TO-39

10.2. Field Of View (FOV)
Point heat source

Sensitivity
100%

50%
Field Of View

Angle of incidence

Rotated sensor

Figure 28: Field Of View measurement
Parameter

Type xAA

Type xBA

Type xCC

Type xCF

Type xCH

Type xCI

Type xCK

Peak zone 1

0°

+25°

0°

0°

0°

0°

0°

Width zone 1

90°

70°

35°

10°

12°

5°

13°

NA

NA

NA

NA

NA

Peak zone 2
Width zone 2

NA

-25°
70°

Table 14: FOV summary table

Figure 29: Typical FOV of MLX90614xAA

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Figure 30: Typical FOV of MLX90614xBA

Figure 31: Identification of zone
1&2 relative to alignment tab

Figure 32: Typical FOV of MLX90614xCC

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Figure 33: Typical FOV of MLX90614xCF

Figure 34: Typical FOV of MLX90614xCH

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Figure 35: Typical FOV of MLX90614xCI

Figure 36 Typical FOV of MLX90614xCK type

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11. Applications Information
11.1. Use of the MLX90614 thermometer in SMBus configuration
+3.3V

R1 R2

3

C1 U2

Vss
4

MCU

SDA
SMBus

SCL 1
Vz

Vdd

U1
Vdd

2
PWM
SDA

SCL
GND

MLX90614Bxx

0.1uF

Figure 37: MLX90614 SMBus connection
Figure 37 shows the connection of a MLX90614 to a SMBus with 3.3V power supply. The MLX90614 has diode clamps SDA /SCL to Vdd so it is necessary MLX90614 to be powered in order not to load the SMBus lines.

11.2. Use of multiple MLX90614s in SMBus configuration
+3.3V

I1

I2

Ipu1

Ipu2

R1
2
PWM
SDA
Vdd
Vss
4

C1 U1

U1

MCU

Vdd
SDA
SMBus

SCL 1
Vz

3

R2

MLX90614Bxx

SCL
Current source or resistor
pull-ups of the bus

GND

0.1uF

C3
Cbus1

2
PWM
SDA
SCL 1
Vz

Vdd
3

C2 U1

Vss
4

Cbus2
C4

MLX90614Bxx

0.1uF
SDA

SCL

Figure 38: Use of multiple MLX90614 devices in SMBus network
The MLX90614 supports a 7-bit slave address in EEPROM, thus allowing up to 127 devices to be read via two common wires.
With the MLX90614xBx this results in 254 object temperatures measured remotely and an additional 127 ambient
temperatures which are also available. Current source pull-ups may be preferred with higher capacitive loading on the bus(C3 and C4 represent the lines’ parasitic), while simple resistive pull-ups provide the obvious low cost advantage.

11.3. PWM output operation
Using the PWM output mode of the MLX90614 is very simple, as shown in Figure 39.

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J1

1
SCL
Vz

Vdd
PWM

PWM
2 SDA

GND
CON1

Vss
U1
MLX90614

Vdd
3

C1

0.1uF

Figure 39: Connection of MLX90614 for PWM output mode
The PWM mode is free-running after POR when configured in EEPROM. The SCL pin must be forced high for PWM mode
operation (can be shorted to VDD pin).
A pull-up resistor can be used to preserve the option for SMBus operation while having PWM as a default as is shown on
Figure 40.
R1
10k

J1
Vdd

1
SCL
Vz

SCL
PWM/SDA

PW M
2 SDA

GND
CON1

Vss
U1
MLX90614

Vdd
3

C1

0.1uF

Figure 40: PWM output with SMBus available
Again, the PWM mode needs to be written as the POR default in EEPROM. Then for PWM operation the SCL line can be highimpedance, forced high, or even not connected. The pull-up resistor R1 will ensure there is a high level on the SCL pin and
the PWM POR default will be active. SMBus is still available (for example – for further reconfiguration of the MLX90614, or
sleep mode power management) as there are pull-up resistors on the SMBus lines anyway.
PWM can be configured as open drain NMOS or a push-pull output. In the case of open drain external pull-up will be needed.
This allows cheap level conversion to lower logic high voltage. Internal pull-ups present in many MCUs can also be used.

11.4. Thermal alert / thermostat
+5V

+24V

+

R1 R2
2
PWM
SDA
SCL 1
Vz

Vdd
3

C1 U1

Vss
4

C1 U1

MLX90614Axx

0.1uF

0.1uF

Vss
4

Q1

MCU
2
PW M
SDA

SDA
SCL 1
Vz

Vdd
3

U1
Vdd

2
PW M
SDA

R1

R2

D1
Alert dev ice

SMBus

GND
MLX90614Bxx

SCL 1
Vz

Vdd
3

SCL

U2

C2

C3

10uF

0.1uF

U1
MLX90614Axx

-

+3.3V

Vss
4

C*

AC lineFigure 41: Thermal alert / thermostat applications of MLX90614
The MLX90614 can be configured in EEPROM to operate as a thermal relay. A non-contact freezing or boiling prevention
with 1 mA quiescent current can be built with two components only – the MLX90614 and a capacitor. The PWM / SDA pin
can be programmed as a push-pull or open drain NMOS, which can trigger an external device, such as a relay (refer toelectrical specifications for load capability), buzzer, RF transmitter or a LED. This feature allows very simple thermostats to
be built without the need of any MCU and zero design overhead required for firmware development. In conjunction with a
MCU, this function can operate as a system alert that wakes up the MCU. Both object temperature and sensor dietemperature can also be read in this configuration.

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11.5. High voltage source operation

J1
V+

MLX90614Axx: V=8...16V

As a standard, the module MLX90614Axx works with a supply voltage of 5Volt. In addition, thanks to the integrated internalreference regulator available at pin SCL / Vz, this module can easily be powered from higher voltage source (likeVDD=8…16V). Only a few external components as depicted in the diagram below are required to achieve this.

PWM
GND
CON1

R1
Q1
C*

Q1

+12V

1 MLX90614
SCL
U1
Vz
4
PWM
Vss
2 SDA

U1
5.7V

Vdd
3

C1
2.2uF

+5V

R1

Equivalent schematics

Figure 42: 12V regulator implementation
With the second (synthesized Zener diode) function of the SCL / Vz pin used, the 2-wire interface function is available only if
the voltage regulator is overdriven (5V regulated power is forced to Vdd pin).

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12. Application Comments
Significant contamination at the optical input side (sensor filter) might cause unknown additional filtering/distortion of the
optical signal and therefore result in unspecified errors.
IR sensors are inherently susceptible to errors caused by thermal gradients. There are physical reasons for these phenomena
and, in spite of the careful design of the MLX90614, it is recommended not to subject the MLX90614 to heat transfer andespecially transient conditions.
Upon power-up the MLX90614 passes embedded checking and calibration routines. During these routines the output is notdefined and it is recommended to wait for the specified POR time before reading the module. Very slow power-up may
cause the embedded POR circuitry to trigger on inappropriate levels, resulting in unspecified operation and this is notrecommended.
The MLX90614 is designed and calibrated to operate as a non-contact thermometer in settled conditions. Using thethermometer in a very different way will result in unknown results.
Capacitive loading on a SMBus can degrade the communication. Some improvement is possible with use of current sources
compared to resistors in pull-up circuitry. Further improvement is possible with specialized commercially available bus
accelerators. With the MLX90614 additional improvement is possible by increasing the pull-up current (decreasing the pullup resistor values). Input levels for SMBus compatible mode have higher overall tolerance than the SMBus specification, but
the output low level is rather low even with the high-power SMBus specification for pull-up currents. Another option might
be to go for a slower communication (clock speed), as the MLX90614 implements Schmidt triggers on its inputs in SMBus
compatible mode and is therefore not really sensitive to rise time of the bus (it is more likely the rise time to be an issue
than the fall time, as far as the SMBus systems are open drain with pull-up).
For ESD protection there are clamp diodes between the Vss and Vdd and each of the other pins. This means that the
MLX90614 might draw current from a bus in case the SCL and/or SDA is connected and the Vdd is lower than the bus pullups’ voltage.
In 12V powered systems SMBus usage is constrained because the SCL pin is used for the Zener diode function. Applications
where the supply is higher than 5V should use the PWM output or an external regulator. Nevertheless, in the 12V powered
applications MLX90614 can be programmed (configured and customized) by forcing the Vdd to 5V externally and running the
SMBus communication.
A sleep mode is available in the MLX90614Bxx. This mode is entered and exited via the SMBus compatible 2-wirecommunication. On the other hand, the extended functionality of the SCL pin yields in increased leakage current throughthat pin. As a result, this pin needs to be forced low in sleep mode and the pull-up on the SCL line needs to be disabled inorder to keep the overall power drain in sleep mode really small. During sleep mode the sensor will not performmeasurements.
The PWM pin is not designed for direct drive of inductive loads (such as electro-magnetic relays). Some drivers need to be
implemented for higher load, and auxiliary protection might be necessary even for light but inductive loading.
It is possible to use the MLX90614 in applications, powered directly from the AC line (transformer less). In such cases it isvery important not to forget that the metal package of the sensor is not isolated and therefore may occur to be connectedto that line, too. Melexis cannot be responsible for any application like this and highly recommends not using the MLX90614
in that way.
Power dissipation within the package may affect performance in two ways: by heating the “ambient” sensitive element
significantly beyond the actual ambient temperature, as well as by causing gradients over the package that will inherently
cause thermal gradient over the cap. Loading the outputs also causes increased power dissipation. In case of using the
MLX90614Axx internal Zener voltage feature, the regulating external transistor should also not cause heating of the TO39
package.

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High capacitive load on a PWM line will result in significant charging currents from the power supply, bypassing thecapacitor and therefore causing EMC, noise, level degradation and power dissipation problems. A simple option is adding aseries resistor between the PWM / SDA pin and the capacitive loaded line, in which case timing specifications have to becarefully reviewed. For example, with a PWM output that is set to 1.024ms and the output format that is 11 bit, the time
step is 0.5μs and a settling time of 2μs would introduce a 4 LSB error.
Power supply decoupling capacitor is needed as with most integrated circuits. MLX90614 is a mixed-signal device withsensors, small signal analog part, digital part and I/O circuitry. In order to keep the noise low power supply switching noiseneeds to be decoupled. High noise from external circuitry can also affect noise performance of the device. In many
applications a 100nF SMD ceramic capacitor close to the Vdd and Vss pins would be a good choice. It should be noted that
not only the trace to the Vdd pin needs to be short, but also the one to the Vss pin. Using MLX90614 with short pins
improves the effect of the power supply decoupling.
Severe noise can also be coupled within the package from the SCL (in worst cases also from the SDA) pin. This issue can besolved by using PWM output. Also the PWM output can pass additional filtering (at lower PWM frequency settings). With asimple LPF RC network added also increase of the ESD rating is possible.
Check www.melexis.com for most recent application notes about MLX90614.

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13. Standard information regarding manufacturability of Melexis productswith different soldering processes
Our products are classified and qualified regarding soldering technology, solderability and moisture sensitivity levelaccording to following test methods:
Wave Soldering THD’s (Through Hole Devices)• EIA/JEDEC JESD22-B106 and EN60749-15
Resistance to soldering temperature for through-hole mounted devices
Iron Soldering THD’s (Through Hole Devices)• EN60749-15
Resistance to soldering temperature for through-hole mounted devices
Solderability THD’s (Through Hole Devices)• EIA/JEDEC JESD22-B102 and EN60749-21
Solderability
For all soldering technologies deviating from above mentioned standard conditions (regarding peak temperature,temperature gradient, temperature profile etc) additional classification and qualification tests have to be agreed upon with
Melexis.
Melexis is contributing to global environmental conservation by promoting lead free solutions. For more information on
qualifications of RoHS compliant products (RoHS = European directive on the Restriction Of the use of certain Hazardous
http://www.melexis.com/quality.aspx
Substances)
pleasevisit
thequality
pageon
our
website:The MLX90614 is RoHS compliant

14. ESD Precautions
Electronic semiconductor products are sensitive to Electro Static Discharge (ESD).
Always observe Electro Static Discharge control procedures whenever handling semiconductor products.

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15. FAQ
When I measure aluminum and plastic parts settled at the same conditions I get significant errors on aluminum.
Why?
Different materials have different emissivity. A typical value for aluminum (roughly polished) is 0.18 and for plastics valuesof 0.84…0.95 are typical. IR thermometers use the radiation flux between the sensitive element in the sensor and the objectof interest, given by the equation

( )
4

( )
4

q = ε1 × α1 × T1 × σ × A1 × Fa −b − ε 2 × T2 × σ × A2 ,Where:
ε1 and ε2 are the emissivities of the two objects,
α1 is the absorptivity of the sensor (in this case),σ is the Stefan-Boltzmann constant,
A1 and A2 are the surface areas involved in the radiation heat transfer,Fa-b is the shape factor,
T1 and T2 are known temperature of the sensor die (measured with specially integrated and calibrated element) and theobject temperature that we need.
Note that these are all in Kelvin, heat exchange knows only physics.
When a body with low emissivity (such as aluminum) is involved in this heat transfer, the portion of the radiation incident tothe sensor element that really comes from the object of interest decreases – and the reflected environmental IR emissions
take place. (This is all for bodies with zero transparency in the IR band.) The IR thermometer is calibrated to stay within
specified accuracy – but it has no way to separate the incoming IR radiation into real object and reflected environmental
part. Therefore, measuring objects with low emissivity is a very sophisticated issue and infra-red measurements of suchmaterials are a specialized field.
What can be done to solve that problem? Look at paintings – for example, oil paints are likely to have emissivity of
0.85…0.95 – but keep in mind that the stability of the paint emissivity has inevitable impact on measurements.
It is also a good point to keep in mind that not everything that looks black is “black” also for IR. For example, even heavily
oxidized aluminum has still emissivity as low as 0.30.
How high is enough? Not an easy question – but, in all cases the closer you need to get to the real object temperature thehigher the needed emissivity will be, of course.
With the real life emissivity values the environmental IR comes into play via the reflectivity of the object (the sum ofEmissivity, Reflectivity and Absorptivity gives 1.00 for any material). The larger the difference between environmental andobject temperature is at given reflectivity (with an opaque for IR material reflectivity equals 1.00 minus emissivity) the bigger
errors it produces.
After I put the MLX90614 in the dashboard I start getting errors larger than specified in spite that the module was working
properly before that. Why?
Any object present in the FOV of the module provides IR signal. It is actually possible to introduce error in the measurements
if the module is attached to the dashboard with an opening that enters the FOV. In that case portion of the dashboard
opening will introduce IR signal in conjunction with constraining the effective FOV and thus compromising specified
accuracy. Relevant opening that takes in account the FOV is a must for accurate measurements. Note that the basic FOV
specification takes 50% of IR signal as threshold (in order to define the area, where the measurements are relevant), while
the entire FOV at lower level is capable of introducing lateral IR signal under many conditions.

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When a hot (cold) air stream hits my MLX90614 some error adds to the measured temperature I read. What is it?
IR sensors are inherently sensitive to difference in temperatures between the sensitive element and everything incident tothat element. As a matter of fact, this element is not the sensor package, but the sensor die inside. Therefore, a thermal
gradient over the sensor package will inevitably result in additional IR flux between the sensor package and the sensor die.
This is real optical signal that cannot be segregated from the target IR signal and will add errors to the measured
temperature.
Thermal gradients with impact of that kind are likely to appear during transient conditions. The sensor used is developedwith care about sensitivity to this kind of lateral phenomena, but their nature demands some care when choosing place to
use the MLX90614 in order to make them negligible.
I measure human body temperature and I often get measurements that significantly differ from the +37°C I expect.
IR measurements are true surface temperature measurements. In many applications this means that the actual temperature
measured by an IR thermometer will be temperature of the clothing and not the skin temperature. Emissivity (explained firstin this section) is another issue with clothes that has to be considered.
There is also the simple chance that the measured temperature is adequate – for example, in a cold winter human hand canappear at temperatures not too close to the well-known +37°C.
I consider using MLX90614AAA to measure temperature within car compartment, but I am embarrassed about the Sun
light that may hit the module. Is it a significant issue?
Special care is taken to cut off the visible light spectra as well as the NIR (near IR) before it reaches the sensitive sensor die.
Even more, the glass (in most cases) is not transparent to the IR radiation used by the MLX90614. Glass has temperature andreally high emissivity in most cases – it is “black” for IR of interest. Overall, Sun behind a window is most likely to introduce
relatively small errors. Why is it not completely eliminated after all? Even visible light partially absorbed in the filter of thesensor has some heating potential and there is no way that the sensor die will be “blind” for that heating right in front of it.

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16. Package Information
16.1. MLX90614xxA
The MLX90614 is packaged in an industry standard TO39 can.

Figure 43: MLX90614xxA package
Note: All dimensions are in mm

16.2. MLX90614xCC

Figure 44: MLX90614xCC package

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16.3. MLX90614xCF

Figure 45: MLX90614xCF package

16.4. MLX90614xCH

Figure 46: MLX90614xCH package

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16.5. MLX90614xCI

Figure 47: MLX90614xCI package

16.6. MLX90614xCK

Figure 48 MLX90614xCK package

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16.7. Part marking
The MLX90614 is laser marked with 10 symbols. First 3 letters define device version (AAA, BCC, etc), and the last 7 are
the lot number. Example: “ACC9307308” – MLX90614ACC from lot 9307308.

16.8. Operating and storage humidity range
Operating and storage humidity range is defined as 85% non-condensing humidity.

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17. Table of figures
Figure 1: Typical application schematics .......................................................................................................................................... 2
Figure 2: Pin description ................................................................................................................................................................. 8
Figure 3: Block diagram .................................................................................................................................................................13
Figure 4: SMBus packet element key ..............................................................................................................................................18
Figure 5: SMBus read word format .................................................................................................................................................19
Figure 6: SMBus write word format ................................................................................................................................................19
Figure 7: Recommended timing on SMBus......................................................................................................................................19
Figure 8: Read word format (SA=0x5A, read RAM=0x07, result=0x3AD2, PEC=0x30) ........................................................................20
Figure 9: Write word format (SA=0x5A, write EEPROM=0x02, data=0xC807, PEC=0x48) ..................................................................20
Figure 10: SMBus timing specification and definition ......................................................................................................................21
Figure 11: Enter sleep mode command (SA = 0x5A, Command = 0xFF, PEC = 0xE8) ..........................................................................22
Figure 12: Exit Sleep Mode ............................................................................................................................................................22
Figure 13: Undershoot of SCL line due to on chip synthesized Zener diode (5V versions only) .........................................................23
Figure 14: PWM timing single (above) and extended PWM (bellow)................................................................................................24
Figure 15: PWM example single mode ............................................................................................................................................25
Figure 16: Extended PWM format with DUAL [5:1] = 01h (2 repetitions for each data) ....................................................................26
Figure 17: Example: Extended PWM mode readings – sensor 1 above and sensor 2 bellow ............................................................26
Figure 18: Switching from PWM mode to SMBus ............................................................................................................................29
Figure 19: Request (switch to SMBus) condition .............................................................................................................................29
Figure 20: Software flow ................................................................................................................................................................32
Figure 21: Thermal relay: “PWM” pin versus Tobj ...........................................................................................................................32
Figure 22: Accuracy of MLX90614 (Ta, To) except for xCK type .......................................................................................................34
Figure 23 Accuracy of MLX90614xCK (Ta, To) only ..........................................................................................................................35
Figure 24: Accuracy of MLX90614DAA (Ta, To) for medical applications. Accuracy of the MLX90614DCC, DCH and DCI for VDD = 3V(see paragraph 10.1.3) ...................................................................................................................................................................36
Figure 25: Typical Ta dependence from supply voltage ...................................................................................................................37
Figure 26: Typical To dependence from supply voltage (practically the same as Ta dependence error .............................................37
Figure 27: Typical To compensated dependence error ....................................................................................................................37
Figure 28: Field Of View measurement ...........................................................................................................................................38
Figure 29: Typical FOV of MLX90614xAA ........................................................................................................................................38
Figure 30: Typical FOV of MLX90614xBA.........................................................................................................................................39
Figure 31: Identification of zone 1&2 relative to alignment tab.......................................................................................................39
Figure 32: Typical FOV of MLX90614xCC .........................................................................................................................................39
Figure 33: Typical FOV of MLX90614xCF .........................................................................................................................................40
Figure 34: Typical FOV of MLX90614xCH ........................................................................................................................................40
Figure 35: Typical FOV of MLX90614xCI ..........................................................................................................................................41
Figure 36 Typical FOV of MLX90614xCK type ..................................................................................................................................41
Figure 37: MLX90614 SMBus connection ........................................................................................................................................42
Figure 38: Use of multiple MLX90614 devices in SMBus network ....................................................................................................42
Figure 39: Connection of MLX90614 for PWM output mode ...........................................................................................................43
Figure 40: PWM output with SMBus available ................................................................................................................................43
Figure 41: Thermal alert / thermostat applications of MLX90614 ....................................................................................................43
Figure 42: 12V regulator implementation .......................................................................................................................................44
Figure 43: MLX90614xxA package ..................................................................................................................................................50
Figure 44: MLX90614xCC package ..................................................................................................................................................50
Figure 45: MLX90614xCF package ..................................................................................................................................................51
Figure 46: MLX90614xCH package ..................................................................................................................................................51
Figure 47: MLX90614xCI package ...................................................................................................................................................52
Figure 48 MLX90614xCK package ...................................................................................................................................................52

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18. References[1] System Management Bus (SMBus) Specification Version 2.0 August 3, 2000
SBS Implementers Forum Copyright . 1994, 1995, 1998, 2000
Duracell, Inc., Energizer Power Systems, Inc., Fujitsu, Ltd., Intel Corporation, Linear Technology
Inc., Maxim Integrated Products, Mitsubishi Electric Semiconductor Company, PowerSmart, Inc.,
Toshiba Battery Co. Ltd., Unitrode Corporation, USAR Systems, Inc.

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19. Contact
For the latest version of this document, go to our website at www.melexis.com.
For additional information, please contact our Direct Sales team and get help for your specific needs:
Europe, Africa

Telephone: +32 13 67 04 95
Email : sales_europe@melexis.com

Americas

Telephone: +1 603 223 2362
Email : sales_usa@melexis.com

Asia

Email : sales_asia@melexis.com

20. Disclaimer
The information furnished by Melexis herein (“Information”) is believed to be correct and accurate. Melexis disclaims (i) any and all liability in connection with or arising out of thefurnishing, performance or use of the technical data or use of the product(s) as described herein (“Product”) (ii) any and all liability, including without limitation, special,consequential or incidental damages, and (iii) any and all warranties, express, statutory, implied, or by description, including warranties of fitness for particular purpose, noninfringement and merchantability. No obligation or liability shall arise or flow out of Melexis’ rendering of technical or other services.
The Information is provided "as is” and Melexis reserves the right to change the Information at any time and without notice. Therefore, before placing orders and/or prior todesigning the Product into a system, users or any third party should obtain the latest version of the relevant information to verify that the information being relied upon is current.
Users or any third party must further determine the suitability of the Product for its application, including the level of reliability required and determine whether it is fit for aparticular purpose.
The Information is proprietary and/or confidential information of Melexis and the use thereof or anything described by the Information does not grant, explicitly or implicitly, toany party any patent rights, licenses, or any other intellectual property rights.
This document as well as the Product(s) may be subject to export control regulations. Please be aware that export might require a prior authorization from competent authorities.
The Product(s) are intended for use in normal commercial applications. Unless otherwise agreed upon in writing, the Product(s) are not designed, authorized or warranted to besuitable in applications requiring extended temperature range and/or unusual environmental requirements. High reliability applications, such as medical life-support or lifesustaining equipment are specifically not recommended by Melexis.
The Product(s) may not be used for the following applications subject to export control regulations: the development, production, processing, operation, maintenance, storage,
recognition or proliferation of 1) chemical, biological or nuclear weapons, or for the development, production, maintenance or storage of missiles for such weapons: 2) civil
firearms, including spare parts or ammunition for such arms; 3) defense related products, or other material for military use or for law enforcement; 4) any applications that, alone
or in combination with other goods, substances or organisms could cause serious harm to persons or goods and that can be used as a means of violence in an armed conflict or any
similar violent situation.
The Products sold by Melexis are subject to the terms and conditions as specified in the Terms of Sale, which can be found at https://www.melexis.com/en/legal/terms-andconditions.
This document supersedes and replaces all prior information regarding the Product(s) and/or previous versions of this document.
Melexis NV © - No part of this document may be reproduced without the prior written consent of Melexis. (2019)
ISO/TS 16949 and ISO14001 Certified

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MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
Revisions Table

VersionRemarkChanges001
002

Preliminary
ReleaseDate
Not on docserver- ordering info (p.1): maximum ratings, accuracy section - added
PWM connection, Application section - remade single zone FOV added PWM details, p. 31 - remove text "filter outside option" wake-up time (page 17) increased from 13 to 80 ms

27 Feb 2007

Added 35 deg. FOV 90614xxC version, FOV specification corrected
and FOV chart's style unified, examples errors corrected (Ta in
RAM), factory default (SMBus) clarified, Pin states (SDA/PWM
automatically switches to NMOS Open Drain when SMBus mode isentered), Application Schematic 10.1 corrected (components'
references U1 U1 changed to U1 U2), emissivity coefficient format
in EEPROM explained, erase before write in EEPROM note added(write 0x0000 first), small grammar and spelling corrections

17 Aug 2007

Added gradient compensated 90614xCC version. Added 10 deg.
FOV 90614xCF version. Added FOV specification of the 90614xCF.
Clarified PWM period EEPROM configuration. Clarified flags readthrough SMBus. Added drawing of the 90614xCF.

09 Jun 2008

005

Some electrical parameters corrected overall revision.

03 May 2009006

Review of electrical parameters, added xCH and xCI parts and their
specific parameters, PWM graphs and examples review, added
VDD dependence of ambient channel, Application comments
update with high speed readings with SMBus, table of figures
added

12 Oct 2010

Changed first page according to new rules. Added DCh and DCI
filter settings. Added note for limitation of highest To of DCh and
DCH. Read write examples are changed to be with SA=0x5A. Better
description of SCL low during sleep. Some parameters arecorrected: Oscillator deviation, Timeout (L and H). Added opticaldistance for some devices (where applicable). Overall revision.

29 Aug 2012

Added –DCC version in ASTM statement on page 33 and in filter
settings table 10.
Page 2: changed from germanium to silicon lens.

29 June 2015

Added xCK versions. Correct PMW to PWM.
TO39 base dimension updated: ∅9.12±0.075

09 June 2017

003

004

008

009

010

∅9.12±0.18011

Drawing dimension xCK corrected

20 March 2018

012
013

Custom version
TO39 base dimension updated:changed from ∅9.12±0.18 to ∅9.12+0.30/-0.18,
added EEPROM write sequence

29 July 201903 Sept 2019

REVISION 13 - 13 SEPTEMBER 2019
3901090614

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