Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

1
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Features and Benefits

Small size single die, low cost 16x4 pixels IR array
Easy to integrate
Industry standard four lead TO-39 package
Factory calibrated. Pixel to pixel relative error below 1.5%
NETD (Noise Equivalent Temperature Difference) 0.2K@4Hz
refresh rate
I2C compatible digital interface
Programmable refresh rate 0.5Hz…512Hz(averaging recommend frame rate 32Hz)
2.6V typical supply voltage
Current consumption less than 9mA
Sleep mode consumption less than 5µA
Measurement start trigger for synchronization with external
control unit
Different package options for applications and measurements
versatility
Ta -40 to 85 °C
To -50 to 1100 °C possible; depending on accuracy requirement

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 1 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

2

General Description

The HTPA 16x4 is a (16x4 pixels) fully calibrated IR array in industry standard four
lead TO-39 package. It contains 2 chips in one package: the HTPA 16x4 (IR array plus
electronics) and the 24AA02 (256x8 EEPROM)
The HTPA 16x4 contains 64 IR pixels with dedicated low noise chopper stabilized
amplifier and fast ADC integrated. A PTAT (Proportional To Absolute Temperature) sensor
is integrated to measure the ambient temperature of the chip. The outputs of both IR
and PTAT sensors are stored in internal RAM and are accessible through I2C.
The results of the infrared sensor measurements are stored in RAM:
 16-bit result of IR measurement for each individual sensor (64 words)
 16-bit result of PTAT sensor
Depending on the application, an external microcontroller can read the different RAM
data and, based on the calibration constants, compensate the different sensitivities ofeach pixel to build up a thermal image, or calculate the object temperature at each pixel
at the imaged scene.
These constants are accessible by the microcontroller through the I2C bus and have to be
used for external post processing of the thermal data. This post processing includes:
 Ta calculation
 Pixel offset cancelling Pixel to pixel sensitivity difference compensation
 Object emissivity compensation
 Object temperature calculation
 Image processing and correction if necessary
The result is an image with NETD better than 0.5K at 1Hz refresh rate.
The refresh rate of the array is programmable by means of EEPROM settings or directly
via I2C command. Changes of the refresh rate have a direct impact on the integration
time and noise bandwidth (faster refresh rate means higher noise level). The refresh rate
is programmable in the range 0,5Hz…512Hz and can be changed to achieve the desired
tradeoff between speed and accuracy.
The HTPA 16x4 requires a single 3V supply (±0,4V).
The customer can choose between 3 operating modes:
 Normal. In this mode the device is free running under control of the internal
state machine. Depending on the selected refresh rate Fps (Frame per second)the chip is constantly measuring both IR and PTAT and is refreshing the data in
the RAM with specified refresh rate; Step. This mode is foreseen for synchronization with an external micro-controller.
The internal state machine is halted. If the command ‘StartMeas’ is received via
the I2C bus, a single measurement of all IR and PTAT sensors will be done, thenthe chip will return in wait state. When in wait state the data in RAM can be read.
 Power saving mode. In this mode all internal electronics will be completely
shutdown and the chip will monitor the I2C. Any transmission through I2C initiatedby Start condition will be detected. The internal oscillator will be powered on andthe device will receive the slave address (SA). If the SA address of HTPA 16x4 is
recognized (SA=0x60) the device will respond, receive and execute the command.
Otherwise the chip will remain in power saving mode. The power saving mode canreduce current consumption down to 5μA and is excellent for battery applications.
The HTPA 16x4 is factory calibrated in wide temperature ranges:
 -40…85 ˚C for the ambient temperature sensor
Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 2 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)-70…300 ˚C for the object temperature (up to 1100°C possible, depending on
accuracy requirement).
All figures are depending on the accuracy requirement.
Each pixel of the array will measure the average temperature of all objects in its own
Field Of View (called FOV).
It is very important for the application designer to understand that the accuracy of thetemperature measurement is very sensitive to the thermal equilibrium 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 thesensor that not only heats the sensing element in the thermometer but also thethermometer package.
This effect is especially relevant for thermometers with a small FOV as the energy
received by the sensor from the object is reduced. Therefore, Heimann Sensor has
integrated the possibility to measure the internal thermal gradients and to compensate
the temperature calculation for them. However, this cannot completely compensate theeffect of thermal gradients. It is therefore important to avoid the causes of thermal
gradients as much as possible or to shield the sensor from them.

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 3 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
Directory
1

Features and Benefits ....................................................................................... 1

2

General Description .......................................................................................... 2

3

Ordering Information ........................................................................................ 6

4

Pin Configuration ............................................................................................. 6

5

Dimensional Drawings ...................................................................................... 7

6

Maximum Ratings ...........................................................................................12

7

Operating Conditions .......................................................................................12

8

Block diagram ................................................................................................14

9

Block description .............................................................................................15
9.1

10
10.1

Array layout ............................................................................................15
Memories ...................................................................................................15
RAM (Result Memory) ...............................................................................15

10.1.1
Configuraton register ..................................................................................................... 17
10.1.2
Trimming register ........................................................................................................... 18
10.2 EEPROM ..................................................................................................19
10.3
11

POR ........................................................................................................21
Communication protocol ...............................................................................21

11.1

Start / Stop condition ...............................................................................21

11.2

Device addressing ....................................................................................22

11.3

Acknowledge ...........................................................................................22

11.4

EEPROM Communication ...........................................................................22

11.5

Sensor Communication .............................................................................22

11.5.1
Measurement trigger...................................................................................................... 22
11.5.2
Read measurement data ............................................................................................... 23
IR data read .................................................................................................................................... 23
PTATdata read ............................................................................................................................... 24
Compensation pixel read................................................................................................................ 24
12
Device modes .............................................................................................24
12.1

Normal mode ...........................................................................................24

12.2

Step mode ..............................................................................................25

12.3

Power saving mode ..................................................................................25

13

Integrated Sensor for gradient compensation ..................................................25

14

Temperature calculation flow ........................................................................27

14.1
15

Initialization ............................................................................................28
Calculation Considerations ............................................................................29

15.1

Calculation of absolute temperature of the die (Ta) ......................................29

15.2

Example for Ta calculations .......................................................................30

15.3

Calculation of To ......................................................................................31

15.4

Calculating VIR(I,j)_COMPENSATED ...........................................................32

15.5

Example for To calculations .......................................................................35

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 4 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
16

Performance Graphs ....................................................................................38

16.1

Temperature accuracy ..............................................................................38

16.2

Noise performance and resolution ..............................................................38

16.3

Calculated Field Of View (FOV) ...................................................................40

17
17.1

Applications Information...............................................................................41
Use of the HTPA 16x4 in I2C configuration ...................................................41

18

Application Comments .................................................................................41

19

Initialization................................................................................................42

20

Liability ......................................................................................................42

21

Glossar ......................................................................................................43

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 5 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

3
HTPA
axb
Rx
L xx
EA

Ordering Information

 Heimann thermopile array number of elements
 Revision of the sensor
 „L“ lens cap TO39 followed by focal length of lens
 optional ending “EA” for external aperture (L3.6 and L5.5 are only
available with the external aperture)

Example: HTPA16x4R1L3.6EA
Currently available are:
- HTPA16x4R1L2.1- HTPA16x4R1L2.85- HTPA16x4R1L3.6EA (standard)- HTPA16x4R1L5.5EA (standard)- HTPA16x4R1L7.0

4

Pin Configuration

Figure 1: pin-allocation
Pin

SymbolDescription

1

SCL

Digital input, serial clock in SMBus compatible mode

2

SDA

Digital I/O, data input /output in SMBus compatible mode (open drain)

3

VDD

Positive supply voltage

4

VSS

Negative supply voltage / Ground (0V) (connected to housing)

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 6 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

5

Dimensional Drawings

Figure 2: dimensional drawing of the HTPA16x4R1L3.6EA

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze
Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX
IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000 0800 4533 00

Page 7 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

Figure 3: dimensional drawing of the HTPA16x4R1L5.5EA

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze
Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX
IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000 0800 4533 00

Page 8 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

Figure 4: dimensional drawing of the HTPA16x4R1L7.0

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 9 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

Figure 5: dimensional drawing of the HTPA16x4R1L2.85

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 10 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

Figure 6: dimensional drawing of the HTPA16x4R1L2.1

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze
Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX
IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000 0800 4533 00

Page 11 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

6

Maximum Ratings

Tab 1: maximum ratings and values
Parameter

HTPA 16x4

Supply Voltage, VDD (over voltage)

5V

Supply Voltage, VDD (operating max)
volvoltagevoltage)
Reverse Voltage (each pin)

3.6V

Operating Temperature Range, TA
Storage Temperature Range, TS
ESD Sensitivity (AEC Q100 002)
DC sink current, SDA
DC source current, SDA
DC clamp current, SDA
DC source current, SCL
DC clamp current, SCL
Pitch
Absorber size
Pixel time constant-0.3 V-40…+85C-40…+125C
2kV (4kV)
25 mA
NA
NA
NA (input only)NA
220 µmØ 170 µm
0.8 msExceeding the absolute maximum ratings may cause permanent damage. Exposure to
absolute-maximum-rated conditions for extended periods may affect device reliability.

7

Operating Conditions

All parameters are valid for TA = 25˚C, VDD =2.6V (unless otherwise specified)Tab 2: operating conditions
Parameter

SymbolTest Conditions

Min

Typ

Max

Units

2.5

2.6

3.3

V

4

5

7

mA

Supplies
1

External supply

VDD

Supply current

IDD

No loadPOR level

VPOR_up

2

2.2

2.4

V

POR level

VPOR_down

1.9

2.1

2.3

V

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

VPOR_hysPower-up (full temp range)
Power–down (full temp
range)
Full temp range

TPOR

Ensure POR signal

100

Power On ResetVµs

I2C compatible 2-wire interface2

Slave addressSA

Factory default

Input high voltage

VIH (Ta, V)

Over temperature and supply

Input low voltage

VIL (Ta, V)

Output low voltage

VOL

Output low voltage

VOL

SCL leakage

ISCL, leak

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

0.1

Over temperature and supply
SDA over temperature andsupply, Isink = 6mA (FMmode)
SDA over temperature
and

60
0.7V
DD

supply, Isink = 20mA (FM+mode)
VSCL=4V, Ta=+85°C

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

hex
V
0.3VD
D
0.6

V

0.4

V

2

µA

V

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Page 12 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
SDA leakage

ISDA, leak

VSDA=4V, Ta=+85°C

2µA

SCL capacitance

CSCL

20

pF

Clock frequency

SCLIR

1

MHz

Acknowledge setup time

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

0.45

µs

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

0.45

µs

Acknowledge setup time

Tsuac(SD)

8-th SCL falling edge, Slave

0.45

µs

Acknowledge hold timeThdac(SD)

9-th SCL falling edge, Slave

0.45

µs

400

kHz

EEPROM
Slave addressSA

Clock frequency

SCLEEPROM

Factory default

50

hex

Data retention

Ta = +85°C

200

years

Erase/write cycles

Ta = +25°C

1M

Times

Ta = +125°C

100K

Erase/write cycles

Times

Erase cell time

T_erase5

ms

Write cell time

T_write5ms1) The device can be supplied with 2.5…3.3 V but the best performance is achieved
at VDD=2.6V. For supply voltages above 2.7V a compensation algorithm should
be applied for accurate temperature readings.

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 13 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

8

Block diagram

HTPA 16x4
Digital Active Thermopile Array
Pix 0,1IR

Pix 0,15IRIR

Pix 1,1IR

Pix 1,15IRIR

Pix 3,1IR

Pix 3,15IR

Pix 0,0IR

Pix 1,0Pix 3,02

EEPROM

RAM

IC

CLK

DigitalConversion& Filtering

SDA

VDD

DigitalFiltering

VSS

Figure 7: block diagram
The device consists of 2 chips packed in single TO-39 packageIR array and processing electronics
EEPROM chip

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 14 of 43

9Block description

Col4

Col5

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

Col15

Col14

Col13

Col12

Col11

Col10

Col9

Col8

Col7

Col6

Col3

Col2

Col1

Col0

9.1 Array layout

Row 0

Row 1
Row 2

Row 3

IR sensor

Figure 8: array layout of IR sensors
The array consists of 64 IR sensors (called also pixels).Each pixel is identified with its row
and column position as Pix(i,j) where i is its row number and j is its column number(from 0 to 15).
Reference pin

Row 0
Row 1
Row 2

Col 15

Col 14

Col 13

Col 12

Col 11

Col 10

Col 9

Col 8

Col 7

Col 6

Col 5

Col 4

Col 3

Col 2

Col 1

Col 0

Row 3

Figure 9: assignment from inside alignment to external reference pin

10 Memories
10.1 RAM (Result Memory)
Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 15 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
The on chip 146x16 RAM is accessible for reading via I2C. The RAM is used for storing theresults of measurements of pixels and Ta sensor and is distributes as follows: 64 words for IR sensors. The data will be in 2’s complement format
 1 word for measurement result of PTAT sensor. This sensor is selected to be areference Ta for the device. The temperatures of all other Ta sensors aremeasured relative to this one. The data is 16 bit without sign. Physically thissensor is placed close to IR(1,1).

Tab. 3: RAM map

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Address

RAM variable description

0x00

IR sensor (0,0) result

0x01

IR sensor (1,0) result

0x02

IR sensor (2,0) result

0x03

IR sensor (3,0) result

0x04

IR sensor (0,1) result

0x05

IR sensor (1,1) result

0x06

IR sensor (2,1) result

0x07

IR sensor (3,1) result

…

…

0x3C

IR sensor (0,15) result

0x3D

IR sensor (1,15) result

0x3E

IR sensor (2,15) result

0x3F

IR sensor (3,15) result

0x40

PTAT sensor result

0x41Compensation sensor result

0x92

Configuration register

0x93

Trimming register

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 16 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
10.1.1 Configuraton register
The configuration register defines the chip operating modes.
It can be read and written by the I2C MD.

Tab. 4: configuration register map
15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

configuration register bit meaning(0x92)- IR Refresh rate = 512Hz- IR Refresh rate = 512Hz- IR Refresh rate = 512Hz- IR Refresh rate = 512Hz- IR Refresh rate = 512Hz- IR Refresh rate = 512Hz- IR Refresh rate = 256Hz- IR Refresh rate = 128Hz- IR Refresh rate = 64Hz
- IR Refresh rate = 32Hz
- IR Refresh rate = 16Hz
- IR Refresh rate = 8Hz- IR Refresh rate = 4Hz- IR Refresh rate = 2Hz- IR Refresh rate = 1Hz (default)- IR Refresh rate = 0.5Hz

0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
0
0 15 – bit resolution*0
1 16 – bit resolution*
1
0 17 – bit resolution*
1
1 18 – bit resolution*0- continuous measurement mode - (default)
1- step measurement mode
- Normal operation mode- (default)- sleep mode

0

0
1
x
NA
0
- No IR measurement running (Flag only, cannot be written)
1- IR measurement running (Flag only, cannot be written) - (default)
0- POR or Brown out occured - Need to reload configuration register1- MD must write "1" during uploading configuration register - (default)
0- I2C FM + mode enabled (max bit transfer rates up to 1000kbits/s) - (default)
1- I2C FM + mode disabled (max bit transfer rates up to 400kbits/s)
00
EEPROM enabled
0
1
EEPROM disabled
0 Heimann Sensor reserved
1 Heimann Sensor reserved
Heimann Sensor reserved* Depending on bits [5:4], the RAM readout represents x2, x4, x8 increased resolution
while maintaining the 16 bits data. This has the effect that for higher resolution readouts,
the maximum measureable temperature is reduced (see 16.2).

Heimann Sensor GmbH
Amtsgericht Dresden
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0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
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Steuer-Nr.: 202/110/07487
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Page 17 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
10.1.2 Trimming register

Tab. 5: trimming register
15 14 13 12 11 10

9

8

7

6

x

x

x

x

NA

x

x

x

x

x

5

4
3
2
7 bit value

10

Trimming register bit meaning (0x93)- Oscillator trim value

Opcode – 0x04.
This command is used to set the trimming parameters – oscillator, bandgap, current
source trimming bits values. It can be read and written by the I2C MD.
Simple data check is introduced. The two data bytes are sent two times: first time withthe true data minus 0xAA and second time – the true data. The chip does the addition
with 0xAA internally and checks the second received byte. Only if the addition results
match with the received data for the two bytes, the configuration register is updated.
The command communication is illustrated below:

S
T
A
R
T

Write trimming Trimming data checkopcodeLSByteSlave address

0 A
C
K

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A
C
K

A
C
K

Trimming data
LSByteTrimming data check
MSByteA
C
K

Trimming data
MSByteA
C
K

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A
C
K

S
T
O
P

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Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

10.2 EEPROM
A 2kbit, organized as 256x8 EEPROM is built in the HTPA 16x4. The EEPROM is on a
separate die (separate SA = 0x50) and is used to store the calibration constants and theconfiguration of the device.

Tab. 6: EEPROM map
Address
00
08
10
18
20
28
30
38
40
48
50
58
60
68
70
78
80
88
90
98
A0
A8
B0
B8
C0
C8
D0
D8
E0
E8
F0
F8

0
ai(0,0)1ai(1,0)2ai(2,0)3ai(3,0)4ai(0,1)5ai(1,1)6
ai(2,1)7ai(3,1)ai(1,15)bi(1,1)ai(2,15)bi(2,1)ai(3,15)bi(3,1)ai - IR pixels individual offset coefficientsai(0,14)bi(0,0)ai(1,14)bi(1,0)ai(2,14)bi(2,0)ai(3,14)bi(3,0)ai(1,15)bi(0,1)bi - Individual Ta dependence (slope) of IR pixels offset

bi(0,14)(0,0)bi(1,14)(1,0)bi(2,14)(2,0)bi(3,14)(3,0)bi(1,15)(0,1)bi(1,15)(1,1)bi(2,15)(2,1)bi(3,15)(3,1)(1,15)(2,15)(3,15)

Individual sensitivity coefficients(0,14)(1,14)(2,14)(3,14)(0,15)

Heimann Sensor
reserved
KT scaleAcommoncompensation pixel coefficients
Scale
TGC
offsetPTAT
common sensitivity coefficients
Emissivity
KsTa
Heimann Sensor reserved
Config register
OSC trim
Chip ID

Detailed descriptions of some EEPROM addresses are depicted here after:
Tab. 7: D7…D0 EEPROM cell meaning – Compensation pixel constants
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Page 19 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
D7

D6

D5

D4

D3

D2

D1

D0

AcommonH AcommonLbCP
cp_Hcp_LaCPL- common offset[7:4] – KT1 scale

KT
scale
aCPH

EEPROM cell meaning[3:0] – KT2 scale - 10

- Compensation pixel individual offset- Individual Ta dependence (slope) of the compensation pixel offset- Sensitivity coefficient of the compensation pixel

Tab. 8: DF…D8 EEPROM cell meaning – PTAT constants
DF

DE

DD

DC

DB

DA

D9

Offset
scale
Vth_H
KT1_H
KT2_H

KT2_L

KT1_L

Vth_L

D8

EEPROM cell meaning- Thermal Gradient
TGC
Coefficient[7:4] - Aiscale[3:0] - Biscale- Vth0 of absolute temperature sensor- KT1 of absolute temperature sensor- KT2 of absolute temperature sensor

Tab. 9: E7…E0 EEPROM cell meaning
E7

E6

E5

E4

E3

E2

E1

E0

EEPROM cell meaning- Common sensitivity coefficient
0_H
0_L
- Common sensitivity coefficient0scale- Individual sensitivity scaling coefficientHLscale- Emissivity coefficient

Heimann Sensor reserved
Tab. 10: F7…F0 EEPROM cell meaning

F7

F6

F5

F4

F3

F2

CFGH

CFGL
- Config register value- Oscillator trimming value

F1

F0

EEPROM cell meaning

Heimann Sensor reserved
OSC_trim

Heimann Sensor GmbH
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Page 20 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

10.3 POR
The Power On Reset (POR) is connected to the Vdd supply. The on-chip POR circuitprovides an active level of the POR signal when the Vdd voltage rises above
approximately 0.5V and holds the entire HTPA 16x4 in reset until the Vdd is higher than
2.4V. The device will start approximately 5 ms after the POR release.

11 Communication protocol
The device supports Fast Mode Plus I2C FM+ (up to 1Mbps) and will work in slave modeonly.
See full I2C specification at: http://www.nxp.com/documents/user_manual/UM10204.pdf
The communication is running through 2 digital pins: SCL and SDA. The master device isproviding the clock signal SCL for the communication. The data line SDA is driven byeither the master or the slave depending on the direction of the communication. A ‘0’ istransmitted by pulling the SDA line to ‘LOW’ and a ‘1’ by releasing it ‘HIGH’. During thedata transfer the SDA must remain stable while SCL is HIGH. Changes in SDA are
allowed only when SCL is LOW.

11.1 Start / Stop condition
Each communication session is initiated by a START condition and ends with a STOP
condition. A START condition is initiated by a HIGH to LOW transition of the SDA while a
STOP is generated by a LOW to HIGH transition. Both changes must be done while the
SCL is HIGH (see the figure)
SCL

SDA

START

STOP

2

Figure 10: Start / Stop conditions of I C

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0800 4533 00

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Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

11.2 Device addressing
The master is addressing the slave device by sending a 7-bit slave address + R/W bit
after the START condition. This bit indicates the direction of the transfer: Read (HIGH) means that the master will read the data from the slave
 Write (LOW) means that the master will send data to the slave
HTPA 16x4 is responding to 2 different slave addresses:

1

0

1

0

0

0

0

R/W

1

1

0

0

0

0

0

R/W

for access to internal EEPROM
for access to IR array chip

11.3 Acknowledge
During the 9th clock following every byte transfer the transmitter releases the SDA line.
The receiver acknowledges (ACK) receiving the byte by pulling SDA line to low or does
not acknowledge (NoACK) by letting the SDA high.

11.4 EEPROM Communication
For further information see datasheet of 24AA02.

11.5 Sensor Communication
11.5.1 Measurement trigger
After the initialization procedure is done depending on the selected measurement mode(bit 6 in the configuration register) there are two possible routines:- continuous mode
- wait for valid data (depending on chosen refresh rates – IR andPTAT)- Step mode
- Send start measurement command
Slave address

CommandSDA
S 1 1

0 0 0 0 0 W A 0 0 0

0 0 0 0 1 A 0 0 0 0 1

0 0 0 AP

SCL

Figure 11: Start measurement command (SA = 0x60, command = 0x0801)
Heimann Sensor GmbH
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Wait certain time

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Page 22 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)-

Wait for the ready flag to be set
11.5.2 Read measurement data

IR data read
There are four options available for reading IR data:- Whole frame read (Heimann Sensor recommends the whole frame read for
maximum refresh rate)
Slave address

CommandStart address

Address step

Number of reads

Slave address

SDA
S 1 1

0 0 0 0 0 W A 0 0 0 0 0 0 1 0 A 0 0 0 0 0 0 0 0 A 0 0 0 0 0 0 0 1 A 0 1 0 0 0 0 0 0 A

S 1 1

0 0 0 0 0 R A

SCLIR pixel(0, 0)
LSByteIR pixel(0, 0)
MSByteIR pixel(1, 0)
LSByteA

IR pixel(1, 0)
MSByteA

IR pixel(3, 15)
LSByteAA

IR pixel(3, 15)MSByteA

A

P

Figure 12 Whole frame (SA = 0x60, command = 0x02, Start address = 0x00,
Address step = 0x01, Number of reads = 0x40) measurement result read-Single column read

Slave address

CommandAddress step

Number of reads

Slave address

Start address

SDA
S 1 1 0 0 0 0 0 W A 0 0 0 0 0 0 1 0 A

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

S1 1 0 0 0 0 0 R A

SCLIR pixel(0, column)
LSByteIR pixel(0, column)
MSByteA

IR pixel(1, column)
LSByteA

IR pixel(1, column)
MSByteA

IR pixel(3, column)
LSByteA

IR pixel(3, column)
MSByteA

A

P

Figure 13 Single column (SA = 0x60, command = 0x02, Start address = 0x00…0x3C (step0x04),
Address step = 0x01, Number of reads = 0x04) measurement result read-Single line read

Slave address

CommandAddress step

Number of reads

Slave address

Start address

SDA
S 1 1 0 0 0 0 0 W A 0 0 0 0 0 0 1 0 A

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

S1 1 0 0 0 0 0 R A

SCLIR pixel(line, 0)
LSByteIR pixel(line, 0)MSByteA

IR pixel(line, 1)
LSByteA

IR pixel(line, 1)
MSByteA

IR pixel(line, 15)
LSByteA

IR pixel(line, 15)MSByteA

A

P

Figure 14 Single line (SA = 0x60, command = 0x02, Start address = 0x00…0x03 (step 0x01),
Address step = 0x04, Number of reads = 0x10) measurement result readHeimann Sensor GmbH
Amtsgericht Dresden
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Page 23 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)-Single pixel read

Slave address

CommandAddress step

Number of reads

Slave address
IR pixel data
LSByteStart address

SDA
S 1 1

0 0 0 0 0 W A 0 0 0 0 0 0 1 0 A

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

S 1 1

0 0 0 0 0 R A

IR pixel data
MSByte
A

A

P

A

P

A

P

SCL

Figure 15 Single pixel (SA = 0x60, command = 0x02, Start address = 0x00…0x3F,
Address step = 0x00, Number of reads = 0x01) measurement result read
PTATdata read
Absolute ambient temperature data of the device itself (package temperature) can beread by using following command:
Slave address

CommandStart address

Address step

Number of reads

Slave address
PTAT data
LSByte

SDA
S 1 1

0 0 0

0

0 W A 0

0 0

0 0

0 1

0 A 0

1 0

0 0

0 0

0 A 0

0 0

0 0

0 0

0 A 0 0 0

0 0

0 0

1 A

S 1 1

0 0

0 0

0

R A

PTAT data
MSByteA

SCL

Figure 16: PTAT (SA = 0x60, command = 0x02, Start address = 0x40,
Address step = 0x00, Number of reads = 0x01) measurement result read

PTAT _ data  { PTAT _ data _ MSbyte : PTAT _ data _ LSbyte}
Compensation pixel read

Slave address

CommandStart address

Address step

Number of reads

Slave address
PTAT data
LSByte

SDA
S 1 1

0 0 0

0

0 W A 0

0 0

0 0

0 1

0 A 0

1 0

0 0

0 0

1 A 0 0 0

0 0

0 0

0 A 0 0 0

0 0

0 0

1 A

S 1 1

0 0 0 00

R A

PTAT data
MSByteA

SCL

Figure 17 Compensation pixel (SA = 0x60, command = 0x02, Start address = 0x41,
Address step = 0x00, Number of reads = 0x01) measurement result read
The 16bit data for each pixel is:

IR(i, j ) _ data  {IR(i, j ) _ data _ MSbyte : IR(i, j ) _ data _ LSbyte}

12 Device modes
The device can operate in following modes:
 Normal mode Step mode
 Power saving mode

12.1 Normal mode
In this mode the measurements are constantly running. Depending on the selected
refresh rate Fps in ConfReg, the data for IR pixels and Ta will be updated in the RAM
each 1/Fps seconds. In this mode the external microcontroller has full access to theinternal registers and memories of the device (both for HTPA 16x4 and EEPROM chip).
Heimann Sensor GmbH
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Page 24 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

12.2 Step modeThis mode is foreseen for single measurements triggered by the external device(microcontroller). Entering this mode is possible by writing the appropriate code in
ConfReg. A measurement is triggered by sending the command StartMeas. On detecting
the command, the HTPA 16x4 will start the measurements immediately after the I2C
session is finished (STOP condition detected). The measurement time is 1/Fps and can beselected in 2 possible ways:
 The already programmed Fps parameter in ConfReg can be used and themeasurement (integration) time will take 1/Fps
 The Fps parameter can be an argument in the StartMeas command.
Once the Step mode is initiated the access to the internal registers of the device will bedisabled. If the master sends a command to the HTPA 16x4 while the measurement instep mode is ongoing, a NoAckn will be received after the slave address is transmitted.
S
T
A
R
T

Slave
address

StartMeas
A
C
K
N

0 A
C
K
N

S
T
A
R
T

S
T
0
P

Slave
address

N
O
A
0
C
K
N

S
T
A
R
T

Slave
address

N
O
A
0 C
K
N

S
T
A
R
T

Slave
address
0 A
C
K
N

1/Fps

Wait for command

Measurement

Wait for command

Figure 18: Execution of Start_Meas in Step mode

12.3 Power saving mode
In this mode the device will be completely shutdown and the current consumption will beminimized to less than 5 µA. Entering this mode is initiated by sending the command‘Sleep’. Upon receiving it the device will shutdown all electronics, including the internal
oscillator. The chip will monitor the I2C line. Each START condition will wake up theoscillator and the chip will receive and evaluate the slave address. If the address is 0x60
(address programmed in HTPA 16x4) the device will evaluate the whole command andwill execute it. If not, the oscillator will be switched off again.

13 Integrated Sensor for gradient compensation
The IR sensor readings and accuracy are very sensitive to any temperature gradientsover the package. Any temperature difference between the cold junction of thermopileand (part of) the package, ‘seen’ by the IR sensor will create an error signal. Such aproblem is not very severe for the applications where absolute measurement is not
required, because in this case it is important to cancel the distortion.
However for the applications where the picture must be converted to temperatures, seenby the different pixels, such a gradient will introduce huge error in the measurement. The
problem will be even more severe if there is a variation of the gradient (unfortunately themost common case, because the gradient comes from power dissipation of electronics on
the same pcb, which varies with environmental conditions).
The HTPA16x4 supports one extra IR channel containing amplifier, ADC and digital filter.
The input of this chain is connected to bond pads. An additional IR sensor can be placed
Heimann Sensor GmbH
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Page 25 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)in the same package and connected to these bond pads. If this sensor is optically‘blinded’ (seeing only package, not outside) its output can be used to compensate theerror readings of the main array.
Heimann Sensor has developed and implemented this approach successfully. The
experience shows that the readings of additional sensor allow reduction of the gradient’s
error by factor of 10.

Heimann Sensor GmbH
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Geschäftsführer:
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Page 26 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

14 Temperature calculation flow
The following algorithm shows an example of a program execution flow to achieve object
as well as ambient temperatures.
POR
Wait 5ms

Read the EEPROMStore the calibration coefficients in the MCU RAM for fast access
Write the oscillator trim value (address 0x93)
Make sure that the POR/Brown Out flag value is ‘1’ (bit 10 in theconfiguration value)
Write the configuration value (address 0x92)
Either read from the EEPROM or hard coded
Yes
POR/Brown Out flag cleared?
No

Step Mode?
Step mode
Continuous mode
Start measurement
Note: In step mode the measurement
end could be determined in 3 ways:
1.Introducing an appropriate delay;
2.By polling the flag;
3.Combination of 1. and 2.

No
Measurement end?
Yes

Read measurement data (desired IR data + PTAT)
Ta calculation
Supply voltage compensation

Pixel offset cancelling
Pixel to pixel normalization
Object emissivity compensation
Object temperature calculation
Image processing and correction

Figure 19: temperature calculation flow

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Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 27 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

14.1 Initialization
After the POR is released the external CPU must execute an initialization procedure.
This procedure must start at least 5ms after POR release.
- Read the whole EEPROM (see Figure 20). For maximum speed performance
Heimann Sensor recommends that the whole calibration data is stored into theclient MCU RAM. However it is possible to read the calibration data from the
EEPROM only when needed. This will result in increased time for temperature
calculation i.e. low refresh rate.
Slave address

Command

Slave address

Initial address - 0x00

DATA(0x00)

DATA(0x01)

DATA(0xFF) K
C
A
N

SDA
S 1

0

1

0

0

0

0

W A 0

0

0

0

0

0 0

0 A

S 1

0

1 0

0

0

0

R A

A

A

P

SCL

Figure 20 Whole EEPROM dump (SA = 0x50)
Store the EEPROM content into customer MCU RAM (see above paragraph for
optional information)
Write the oscillator trimming value (extracted from EEPROM content ataddress 0xF7) into the corresponding register (0x93).

-

Slave address

Command
LSByte check(LSByte - 0xAA)

SDA
S 1 1

0

0

0

0

0

W A 0

0

0

0 0

1 0

0 A

MSByte check(MSByte - 0xAA)

LSByte data
A

A

MSByte data
A

A

P

A

P

SCL

Figure 21 Write oscillator trimming (SA = 0x60, command = 0x04)
Write device configuration value. In EEPROM addresses (0xF5 and 0xF6)
Heimann Sensor provides a typical value of the configuration register(0x740E). So it is up to the user to copy that value or hardcode a new value tobe loaded into the configuration register. If the EEPROM value is to be usedthe 16 bits are combined as follows:-

For instance if EEPROM 0xF5 = 0x0E and 0xF6 = 0x74, the Configuration
register value is:

Configurat ion _ register _ value  {0 xF 6 : 0 xF 5}  0 x740E
Slave address

Command
LSByte check(LSByte - 0x55)

SDA
S 1 1

0 0 0 0 0 W A 0 0 0 0 0 0 1 1 A

MSByte check(MSByte - 0x55)

LSByte data
A

A

MSByte data
(15:11)
A

(9:8)
1

SCL

Figure 22 Write configuration register (SA = 0x60, command = 0x03)
NOTE: The customer must ensure that the bit 10 (POR or Brown-out flag) in
Configuration register is set to “1” by the MD. Furthermore this bit must be
checked regularly and if it is cleared that means that the device has been reset
and the initialization procedure must be redone.
Opcode – 0x03.

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 28 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
This command is used to set the configuration register (16bits) value – all configuration
settings.
Simple data check is introduced. The two data bytes are sent two times: first time withthe true data minus 0x55 and second time – the true data. The chip does the addition
with 0x55 internally and checks the second received byte. Only if the addition results
match with the received data for the two bytes, the configuration register is updated.
The command communication is illustrated below:

S
T
A
R
T

Slave address

Write configuration Confuguration data Confuguration data Confuguration data Confuguration dataregister opcode
check LSByte
LSBytecheck MSByte
MSByte

0 A

A
C
K

C
K

A
C
K

A
C
K

A
C
K

A
C
K

S
T
O
P

Figure 23: Write configuration register command
The default configuration is:- IR refresh rate = 1Hz- Ta refresh rate = 0.5Hz- Continuous measurement mode
- Normal mode (no sleep)- I2C FM+ mode (max bit transfer rates up to 1000 kbit/s) enabled- ADC low reference enabled

15 Calculation Considerations
15.1 Calculation of absolute temperature of the die (Ta)The output signal of the IR sensor is relative to its cold junction temperature. That is why
we need to know the absolute temperature of the die in order to be able to calculate theobject temperature ‘seen’ by each pixel.
The Ta can be calculated using the formula: K T 1  K T 1  4 K T 2 VTH 25  PTAT _ data 2Ta 

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

2KT 2

 25,[C ]Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 29 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
Constants VTH (25) , K T 1 and KT 2 are stored in EEPROM at following addresses as two’s
complement values:

Tab. 11: absolute temperature values storage adress
EEPROM address

Cell name

0xDA
0xDB

VTH_L
VTH_H

0xDC
0xDD
0xDE
0xDF

KT1_L
KT1_H
KT2_L
KT2_H

0xD2

KT_scaleStored as

2’s complement VTH0 of absolute temperature sensor
2’s complement

KT1 of absolute temperature sensor

2’s complement

KT2 of absolute temperature sensor

unsigned

VTH 25  256  VTH _ H  VTH _ L Parameter [7:4] – KT1_scale[3:0] – KT2_scale 

If VTH 25  32767  VTH 25  VTH 25  65536

VTH 25 

25

V

TH
3  ConfigRe g [ 5:4 ]2

KT 1  256  KT 1 _ H  KT 1 _ L
If KT 1  32767  KT 1  KT 1  65536

KT 1 

2

K T 1 _ scale

KT 1
 23 ConfigRe g [5:4]

KT 2  256  KT 2 _ H  KT 2 _ L
If KT 2  32767  KT 2  KT 2  65536

KT 2 

2

K T 2 _ scale 10

KT 2 23ConfigRe g [5:4]

15.2 Example for Ta calculations
Let’s assume that the values in EEPROM are as follows:

Tab. 12: examples of cell values written in the EEPROM
EEPROM address

Cell name

0xDA
0xDB
0xDC
0xDD
0xDE

VTH_L
VTH_H
KT1_L
KT1_H
KT2_L

Cell values
(hex)
0x78
0x1A
0x33
0x5B
0xCC

0xDF

KT2_H

0xED

VTH 25  256 VTH _ H  VTH _ L  256  26  120  6776 , decimal value
Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 30 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr) 

Sign check 6776  32767  VTH 25  6776

 

ConfigReg[5:4]=3  VTH 25  6776

KT 1 _ scale  10
KT 1  256  KT 1 _ H  KT 1 _ L  23347
Sign check 23347 < 32767  KT 1  23347

KT 1 

2

K T 1 _ scale

KT 1
23347

 22.7998
3  ConfigRe g [ 5:4 ]1024
2

KT 2 _ scale  10
KT 2  256  KT 2 _ H  KT 2 _ L  256  237  204  60876
Sign check 60876  32767  KT 2  60876  65536  4660

KT 2 

2

K T 2 _ scale 10

KT 2
 4660 0.0044441
3  ConfigRe g [ 5:4 ]10485762

Let’s assume that the input data is:

PTAT _ data  0x1AC0 = 6848 dec
Thus the ambient temperature is: K T 1  K T 1  4 K T 2 VTH (25)  PTAT _ data 
2

Ta 

2KT 2

Ta 

 22.7998  519.8309  4(0.0044441)6776  6848
 25
 0.0088882

Ta 

 22.7998  519.8309  0.0177764 72
 25
 0.0088882

Ta 

 22.7998  518.551
 22.7998  22.7717
 25 
 25  3.16  25
 0.0088882
 0.0088882

Ta  28.16C
15.3 Calculation of To
Following formula is used to calculate the temperature seen by specific pixel in thematrix:Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 31 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

TO (i , j )  4 VIR (i , j ) _ COMPENSATED  Ta  273.15  273.15,[C ]4where:

VIR (i , j ) _ COMPENSATED is the parasitic free IR compensated signal

Ta is ambient temperature calculated in 9.4.2
15.4 Calculating VIR(I,j)_COMPENSATED
1. Offset compensation

VIR (i , j ) _ OFF _ COMP  VIR (i , j )  Ai (i , j )  Bi (i , j )  Ta  Ta _ 0 

Where:

VIR (i , j ) is a individual pixel IR_data readout (RAM read)Ai (i , j ) is a individual pixel offset restored from the EEPROM using thefollowing formula:Ai (i , j ) 

Acommon  ai (i , j )  2 AiScale
23ConfigRe g [5:4]

Acommon is the minimum offset value stored in the EEPROM at addresses
0xD0 and 0xD1 as 2’s complement valueai (i , j ) is the difference between the individual offset and the minimum
value. It is stored in the EEPROM as unsigned values.
AiScale is the scaling coefficient for the ai (i , j ) values and is stored in the
EEPROM at address 0xD9[7:4] as an unsigned value

Bi (i , j ) is an individual pixel offset slope coefficient
Bi (i , j ) bi (i , j )2

BiScale 23ConfigRe g [5:4]bi(i , j ) is the value stored in EEPROM as two’s complements

BiScale is a scaling coefficient for the slopes of IR pixels offset and is stored
in the EEPROM at address 0xD9[3:0] as an unsigned value
Ta is the ambient temperature calculated in 15.1

Ta _ 0  25C is a constant
NOTE: This applies to the compensation pixel as well ( aCP and bCP while BiScale is thesame)

2. Thermal Gradient Compensation (TGC)
Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 32 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

VIR (i , j ) _ TGC _ COMP  VIR (i , j ) _ OFF _ COMP  TGC  VIR _ CP _ OFF _ COMP
Where:

VIR _ CP _ OFF _ COMP is the offset compensated IR signal of the thermal gradientcompensation pixel

TGC 

TGCEEPROM
32

TGCEEPROM is a coefficient stored at EEPROM address 0xD8 as a two’s
complement value
3. Pixel to pixel normalization

VIR (i , j ) _ NORMALIZED 

VIR (i , j ) _ TGC _ COMP

 (i , j )  TGC   CP

Where:

256   0 _ H   0 _ L

 (i , j )  CP 



 0 _ SCALE

2

23ConfigRe g [5:4]
256   CP _ H   CP _ L

 (i , j )2  SCALE

2 0 _ SCALE  23ConfigRe g [5:4] 0 _ H ,  0 _ L ,  CP _ H ,  CP _ L ,  (i , j ) ,  0 _ SCALE and  SCALE are stored in the
EEPROM as unsigned values
4. Emissivity compensation

VIR (i , j ) _ COMPENSATED 

VIR (i , j ) _ NORMALIZEDWhere:
 is the emissivity coefficient. The scaled value is stored into EEPROM as
unsigned value

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

256   H   L
32768

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 33 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

Parameters necessary to calculate To are stored into EEPROM at following addresses:

Tab 13: parameter used in calculation
EEPROMaddress

Cell nameStored asParameter

0x00…0x3F

ai ( i , j )unsigned

IR pixel individual offset delta coefficient

0x40…0x7F

bi (i , j )2’s complement

0x80…0xBF (i , j )Individual Ta dependence (slope) of IR
pixels offset

unsigned

Individual sensitivity coefficient

0xD0

Acommon_ L

0xD1

Acommon_ H

2’s complement

IR pixel common offset coefficient

0xD3

aCP _ L

0xD4

aCP _ H2’s complement

Compensation pixels individual offset
coefficients

0xD5

bCP

2’s complement

0xD6 CP _ L

Individual Ta dependence (slope)of the compensation pixel offset

0xD7

 CP _ H

unsigned

Sensitivity coefficient of the compensation
pixel

0xD8

TGC

2’s complement

0xD9

AiScale, BiScaleunsigned

0xE0

0_ L

0xE1

0_ H

0xE2

Thermal gradient coefficient
Scaling coefficients for the IR pixels offset
deltas and the slope of the IR pixels offset

unsigned

Common sensitivity coefficient of IR pixels

 0 _ SCALE

unsigned

Scaling coefficient for common sensitivity

0xE3

 SCALE

unsigned

Scaling coefficient for individual sensitivity

0xE4

L
H

unsigned

Emissivity

0xE5

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 34 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

15.5 Example for To calculations
Let’s assume that we have following EEPROM data for pixel i=2, j=8:

Tab 14: example of values while calculating object temperature
EEPROM address

Cell nameStored as

Cell values (hex)0x22ai ( 2 ,8 )unsigned

0x2D

0x62

bi ( 2,8)

0xC1

0xA2

 ( 2,8)

2’scomplement
unsigned

0x8F

0xD0

Acommon_ L

0x96

0xD1

Acommon_ H

2’scomplement

0xD3

aCP _ L

0xC8

0xD4

aCP _ H2’scomplement

0xD5

bCP

0xD6

 CP _ L

2’scomplement

0xD7

 CP _ H

0xD8

TGC

2’s
complement

0x18

0xD9

AiScale, BiScaleunsigned

0x07

0xE0

0_ L

unsigned

0xE4

0xE1

0_ H

unsigned

0xD5

0xE2

 0 _ SCALE

unsigned

0x2A

0xE3

 SCALE
 _L
 _H

unsigned

0x21

unsigned

0x9A

unsigned

0x79

0xE4
0xE5

unsigned

0xFF

0xFF
0xCA
0x80
0x09

Let’s assume that we have the following input data:

VCP  0 xFFD8  65496 , decimal value
Sign check 65496  32767  VCP  65496  65536  40

VIR ( 2,8)  0 x0090  144 , decimal value
Sign check 144  32767  VIR ( 2,8)  144

Ta  28.16C (as calculated in 15.1)
Reference routine for To computation:aCP  256  aCP _ H  aCP _ L  65480 , decimal value
Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 35 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
Sign check 65480  32767  aCP  65480  65536  48

ACP 

a

2

CP
3ConfigRe g [ 5:4 ] 48

bCP  0 xCA  202 , decimal value
Sign check 202  127  bCP  202  256  54

 54
 0.4219
27  202
2
VIR _ CP _ OFF _ COMP  VCP  ACP  BCP  Ta  Ta _ 0   40   48  0.4219  28.16  25  9.33
b

BCP 

CP
3ConfigRe g [ 5:4 ]BiScale

ACommon  256  ACommon_ H  ACommon_ L  65430
Sign check 65430  32767  ACommon  65430  65536  106

ai ( 2,8)  0 x2D  45 , decimal value

Ai ( 2,8) 

Acommon  ai ( 2,8)  2 AiScale
23ConfigRe g [5:4] 106  45  20
 61
20

bi ( 2,8)  0 xC1  193 , decimal value
Sign check 193  127  bi ( 2,8)  193  256  63

 63
 0.4922
27  202
2
VIR ( 2,8) _ OFF _ COMP  VIR ( 2,8)  Ai ( 2,8)  Bi ( 2,8)  Ta  Ta _ 0   144   61  0.4922  28.16  25  81.44
Bi ( 2,8) bi ( 2,8)

BiScale3ConfigRe g [ 5:4 ]

TGCEEPROM  0 x18  24 , decimal value
Sign check 24  127  TGCEEPROM  24

TGCEEPROM 24 0.7532
32
VIR (i , j ) _ TGC _ COMP  VIR (i , j ) _ OFF _ COMP  TGC  VIR _ CP _ OFF _ COMP  81.44  0.75  9.33  74.44
TGC 

256   0 _ H   0 _ L

 ( 2,8)256  213  228 143
 33
2
2
2 42
2  2.9097  10 8 ( 2 ,8 ) 3ConfigRe g [ 5:4 ]0
2
2
256   CP _ H   CP _ L
2432
 CP  0 _ SCALE 3ConfigRe g [5:4]  42 0  5.5297  10 10
2 2
2
2
VIR ( 2,8) _ TGC _ COMP
74.44
VIR ( 2,8) _ NORMALIZED  2522387075
8
 ( 2,8)  TGC   CP 2.9097  10  0.75  5.5297  10 10
 0 _ SCALE

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

 SCALE

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 36 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)256   _ H   _ L 256  121  154 31130

 0.95
32768
32768
32768

VIR ( 2,8) _ COMPENSATED 

VIR ( 2,8) _ NORMALIZED



2522387075
 2655144289
0.95

TO ( 2,8)  4 VIR ( 2,8) _ COMPENSATED  Ta  273.15  273.15
4TO ( 2,8)  4 2655144289  28.16  273.15  273.15  49.95C
4

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 37 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

16

Performance Graphs
16.1 Temperature accuracy

All accuracy specifications apply under settled isothermal conditions only.
Furthermore, the accuracy is only valid if the object fills the FOV of the sensor
completely.

Figure 24: Absolute temperature accuracy for the central four pixels
NOTE: The accuracy is specified for the four central pixels. The accuracy of the rest of
the pixels is according to the uniformity statement

16.2 Noise performance and resolution
There are two bits in the configuration register that allow changing the resolution of the
HTPA16x4R1 measurements. Increasing the resolution decreases the quantization noise
and improves the overall noise performance.

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 38 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

Figure 25: Central pixels noise

Figure 26: Corner pixels noise
A higher resolution limits the maximum object temperature range of the HTPA16x4R1.

Tab 15: Maximum object temperature at different resolution settings
Configuration register [5,4], bin

Resolution

Maximum object temperature in °C

00

15 bits~1100

01

16 bits~900

1017 bits~700

11

18 bits~500

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 39 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
NOTE: If the object temperature exceeds the maximum object temperature specified forthe corresponding resolution, the HTPA16x4R1 may return invalid data due tomeasurements overflow.

16.3 Calculated Field Of View (FOV)The FOV must be separated in this case in two directions, because the HTPA 16x4 has 16
sensors in the width and 4 in the height.

Tab. 16: calculated field of view (FOV)parameter

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

unit
16 sensors

4 sensors

Field of View
L7.0

28.22

7.19

degreeField of View
L5.5EA

35.49

9.15

degreeField of View
L3.6EA

52.11

13.94

degreeField of View
L2.85

63.39

17.55

degreeField of view
L2.1

90

23.7

degreeGeschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 40 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

17

Applications Information

17.1 Use of the HTPA 16x4 in I2C configuration
+3.3V

R1 R2
2
SDA
3

I2C

SCL 1

Vdd

Vss
4 HTPA 16x4

C1 U2
0.1uF

U1

MCU

Vdd
SDA
SCL
GND

Figure 27: wire connection I2C
Figure 27shows the connection of a HTPA 16x4 to an I2C with 3.3V power supply. The
HTPA 16x4 has diode clamps SDA/SCL to Vdd so it is necessary to provide HTPA 16x4
with power in order not to load the I2C lines.

18

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 from thefront lens to the sensor die. This phenomenon is called “heat shock”. When the front
cap or lens emits more heat than the sensor die, the sensor receives more heat than it
can compensate itself from its own ambient heat. Therefore the sensor is “shielded” andis not able to measure in specified ranges. In spite of the careful design of the HTPA 16x4
it is recommended not to subject the HTPA 16x4 to heat transfer and especially transientconditions. Front cap, front fens and sensor die should have the same ambient
temperature.
The HTPA 16x4 is designed and calibrated to operate as a non contact thermometer insettled conditions. Using the thermometer in a very different way will lead to unknown
results.
Capacitive loading on a I2C can degrade the communication. Some improvement ispossible with use of current sources compared to resistors in pull-up circuitry. Further
improvement is possible with specialized commercially available bus accelerators. With
the HTPA 16x4 additional improvement is possible by increasing the pull-up current(decreasing the pull-up resistor values). Input levels for I2C compatible mode havehigher overall tolerance than the I2C specification, but the output low level is rather low
even with the high-power I2C specification for pull-up currents. Another option might beto go for a slower communication (clock speed), as the HTPA 16x4 implements Schmidt
triggers on its inputs in I2C compatible mode and is therefore not really sensitive to risetime of the bus (it is more likely the rise time to be an issue than the fall time, as far as
the I2C systems are open drain with pull-up).
Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 41 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)
Power dissipation within the package may affect performance in two ways: byheating 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.
Power supply decoupling capacitor is needed as with most integrated circuits.
HTPA 16x4 is a mixed-signal device with sensors, small signal analog part, digital partand I/O circuitry. In order to keep the noise low power supply switching noise needs tobe decoupled. High noise from external circuitry can also affect noise performance of thedevice. 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 pinneeds to be short, but also the one to the Vss pin. Using HTPA 16x4 with short pins
improves the effect of the power supply decoupling.

19 Initialization
After POR is released the chip executes an initialization procedure, this procedure starts
typ. 16ms after POR release and requires only a few ms. In that time the device will readits configuration from the reserved part of the EEPROM and will load it in the registers ofthe HTPA16x4. The settings that are loaded are:•Oscillator trimming data•
Bias trimming data•
Regulator control•
ConfReg settings
During that time the HTPA16x4 will work as Master I2C device for the EEPROM chip. Notethat this will not affect the external I2C bus, i.e. the information transmitted between
HTPA16x4 and EEPROM chip will not be visible externally.
During the initialization, the HTPA16x4 will block any access through external I2C line
and will not respond to any commands. This means that a NoACKN will be received by
the external MCU if the HTPA16x4 or EEPROM chip is addressed.

20 Liability
The contents of this document are subject to change without notice.
Changes or modifications at the product which haven't influence to the performance
and/or quality of the device haven't to be announced to the customers in advance.
Customers are requested to consult with Heimann Sensor representatives before the useof Heimann Sensor products in special applications where failure or abnormal operation
may directly affect human lives or cause physical injury or property damage. The
company or their representatives will not be responsible for damage arising from suchuse without prior approval.

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 42 of 43

Thermopile Array With Lens Optics
Type HTPA 16x4R1
Rev. 2: 15.07.2015 (Schnorr)

21 Glossar
ADC
DSP
EMC
ESD
FOV
FpS
HFO
I2C
IR

MD
NA
POR
PTAT
SCL
SD
SDA
Ta

Analog to Digital Converter
Digital Signal Processing
Electro-Magnetic Compatibility
Electro-Static Discharge
Field Of View
Frames per Second (data refresh rate)
High Frequency Oscillator (RC type)Inter-Integrated Circuit communication protocol
Infra RedInfra Red data (raw data from ADC proportional to IR energy received
from the sensor)
Master Device
Not Applicable
Power On Reset
Proportional To Absolute Temperature sensor (package temperature)
Serial CLockSlave Device
Serial Data
Ambient Temperature

TGC
TBD
To

Temperature Gradient Coefficient
To Be Defined
Object Temperature, ‘seen’ from IR sensor

IR_data

Heimann Sensor GmbH
Amtsgericht Dresden
HRB 20692
0800 4533 00

Geschäftsführer:
Dr. Jörg Schieferdecker
Mischa Schulze

Ostsächsische Sparkasse Dresden
SWIFT-Code: SOLADEST
BIC: OSDDDE81XXX

Steuer-Nr.: 202/110/07487
Ust-Ident-Nr.: DE 813444739

IBAN: DE03 8505 0300 3120 0454 02 (EUR)
IBAN: DE40 8505 0300 0229 0000 88 (USD)

Commerzbank AG
BIC: COBADEFF850
IBAN: DE77 8504 0000

Page 43 of 43