CCS811
Ultra-Low Power Digital Gas Sensor for
Monitoring Indoor Air Quality
General Description

The CCS811 is an ultra-low power digital gas sensor solution
which integrates a metal oxide (MOX) gas sensor to detect awide range of Volatile Organic Compounds (VOCs) for indoor
air quality monitoring with a microcontroller unit (MCU), which
includes an Analog-to-Digital converter (ADC), and an I²C
interface.
CCS811 is based on ams unique micro-hotplate technology
which enables a highly reliable solution for gas sensors, very
fast cycle times and a significant reduction in average power
consumption.
The integrated MCU manages the sensor drive modes and raw
sensor data measured while detecting VOCs. The I²C digitalinterface significantly simplifies the hardware and software
design, enabling a faster time to market.
CCS811 supports intelligent algorithms to process raw sensor
measurements to output a TVOC value or equivalent CO 2 (eCO2)
levels, where the main cause of VOCs is from humans.
CCS811 supports multiple measurement modes that have been
optimized for low-power consumption during an active sensor
measurement and idle mode extending battery life in portableapplications.
CCS811 is available in a 10 lead 2.7mm x 4.0mm x 1.1mm, 0.6mm
pitch LGA package.
Ordering Information and Content Guide appear at end ofdatasheet.

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Page 1Document FeedbackCCS811 − General Description

Key Benefits & Features
The benefits and features of CCS811, Ultra-Low Power Digital
Gas Sensor for Monitoring Indoor Air Quality are listed below:
Figure 1:
Added Value of Using CCS811 Sensor

Benefits

Features• Manages the sensor drive modes andmeasurements while detecting VOCs

• Integrated MCU• Provides eCO2 level or TVOC indication with no hostintervention• On-board processing• Simplifies the hardware and software integration• Standard I²C digital interface• Extend battery life in portable applications• Optimised low-power modes• Suitable for small form-factor designs• 2.7mm x 4.0mm x 1.1mm LGA package• Saves up to 60% in PCB footprint• Low component count• Designed for high volume and reliability(>5years lifetime)• Proven technology platform

Applications
This device can be mainly used for indoor air quality
monitoring in:• Smart phones• Wearables• Home and Building automation• Accessories

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CCS811 − General Description

Block Diagram
The functional blocks of this device are shown below:
Figure 2:
CCS811 Block Diagram

VDD

SDA

6

10

SCL

9

1
ADDR

AUX

8

H+

(With Integrated ADC)nRESET

7

EP

4

Sense

PWM

H-

nWAKE

2

MCU

nINT

GND

3

S+

MOX
Gas Sensor
S-

5
Pins 4 and 5 must beconnected together

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Page 3Document FeedbackCCS811 − Pin Assignment

Pin Assignment
Figure 3:
Pin Diagram

Pin 1 Corner
Index Area

(Bottom View)(Top View)

5

6

4

7
8

3
2

9

1
10

Pin 1 Corner
Index Area

Pin Diagram: The Exposed Pad is underneath
Figure 4:
CCS811 LGA Pin Assignment

Pin No.

Pin Name

1

ADDR

Single address select bit to allow alternate address to be selected• When ADDR is low the 7 bit I²C address is decimal 90 / hex 0x5A
• When ADDR is high the 7 bit I²C address is decimal 91 / hex 0x5B.

2

nRESETnRESET is an active low input and is pulled up to VDD by default. nRESET is
optional but 4.7kΩ pull-up and/or decoupling of the nRESET pin may benecessary to avoid erroneous noise-induced resets. This pin will be pulled low
internally during reset.

3

nINT

nINT is an active low optional output. It is pulled low by the CCS811 to indicate
end of measurement or a set threshold value has been triggered.

4

PWM

Heater driver PWM output. Pins 4 and 5 must be connected together.

5

Sense

Heater current sense. Pins 4 and 5 must be connected together.

6

VDD

Supply voltage.

7

nWAKE

nWAKE is an active low input and should be asserted by the host prior to an I²C
transaction and held low throughout.

8

AUX

Optional AUX pin which can be used for ambient temperature sensing with an
external NTC resistor. If not used leave unconnected.

9

SDA

SDA pin is used for I²C data. Should be pulled up to VDD with a resistor.

10

SCL

SCL pin is used for I²C clock. Should be pulled up to VDD with a resistor.

EP

Exposed Pad

Page 4Document Feedback

Description

Connect to ground.

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CCS811 − Absolute Maximum Ratings

Absolute Maximum Ratings

Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. These are stressratings only. Functional operation of the device at these or any
other conditions beyond those indicated under Electrical
Characteristics is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect device
reliability

Figure 5:
Absolute Maximum Ratings

SymbolParameter

Min

Max

Units

3.6

V

Comments

Electrical Parameters
VDD (1)

Supply Voltage

IDD

Supply Current

30

mA

In mode 1

P

Power Consumption

60mW

In mode 1

1.8(2)

Electrostatic Discharge
ESDHBM

Human Body Model

±2000

V

Environmental Conditions
TAMB

Ambient Temperature for Operation

-5

50

o

TSTRG

Storage Temperature

-40

125

o

RHNC

Relative Humidity (non-condensing)

10

95

%

LT (3)

Product Lifetime

>5

MSL

Moisture Sensitivity Level

1

C
C

Years

In mode 1
Unlimited max.
floor life time

Note(s):1. The supply voltage V DD is sampled during boot and should not vary during operation.
2. The minimum supply voltage V DD is 1.8V and should not drop below this value for reliable device operation.
3. Product lifetime for CCS811 will be longer in modes 2 and 3.

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Page 5Document FeedbackCCS811 − Electrical Characteristics

Electrical Characteristics
Figure 6:
Electrical Characteristics

Parameters

Conditions

Min

Supply Voltage (VDD) (1), (2)Supply Current (IDD) (3)Typ (6)

1.8

Max

Units

3.3

V

During measuring at 1.8V

26

mA

Average over pulse cycle(3) at 1.8V

0.7

mA

Sleep Mode at 1.8V

19

μA

Idle Mode 0 at VDD= 1.8V

0.034

mW

Mode 1 & 4 at VDD= 1.8V

46mW

Mode 2 at VDD= 1.8V

7mW

Mode 3 at VDD= 1.8V

1.2

mW

Power Consumption

Logic High Input (5)nRESET, nWAKE, ADDR

VDD 0.6

VDD

V

Logic Low Input (5)nRESET, nWAKE, ADDR

0

0.6

V

Logic High OutputnINT

Logic Low Output

nINT

Analogue Input

AUX

VDD 0.7

0

V
0.6

V

VDD

V

Note(s):1. The supply voltage V DD is sampled during boot and should not vary during operation
2. The maximum VDD ramp time for Power On is 3ms
3. Typical values for 1.8V supply voltage (V DD)
4. Average Supply Current (I DD) for a sensor measurement once every 60 seconds
5. For SDA and SCL timing refer NXP I²C – bus specification and user manual UM10204
6. Typical values at 25 oC and 50% RH

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CCS811 − Electrical Characteristics

Figure 7:
Timing Characteristics

Parameters

Conditions

Min

Typ

Max

Units

tAWAKE (1)Time until active after nWAKE asserted.

50

μs

tDWAKE

Minimum time nWAKE should bede-asserted

20

μs

tRESET

Minimum nRESET low pulse

20μsTime until active after Power on

18

20

ms

Time until active after nRESET

1

2

ms

100

400

kHz

tSTART (2)fI²C

Frequency of I²C Bus Supported

10Note(s):1. nWAKE should be asserted prior to and during any I²C transaction
2. Up to 70ms on the first Reset after new application download

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Document FeedbackCCS811 − Detailed Description

Detailed Description
Modes of Operation
The CCS811 has 5 modes of operation as follows• Mode 0: Idle, low current mode
• Mode 1: Constant power mode, IAQ measurement every
second• Mode 2: Pulse heating mode IAQ measurement every 10
seconds• Mode 3: Low power pulse heating mode IAQ
measurement every 60 seconds• Mode 4: Constant power mode, sensor measurement
every 250ms
In Modes 1, 2, 3, the equivalent CO 2 concentration (ppm) andTVOC concentration (ppb) are calculated for every sample.
• Mode 1 reacts fastest to gas presence, but has a higher
operating current• Mode 3 reacts more slowly to gas presence but has thelowest average operating current.
When a sensor operating mode is changed to a new mode witha lower sample rate (e.g. from Mode 1 to Mode 3), it should beplaced in Mode 0 (Idle) for at least 10 minutes before enabling
the new mode. When a sensor operating mode is changed to a
new mode with a higher sample rate (e.g. from Mode 3 to Mode1), there is no requirement to wait before enabling the newmode.
Mode 4 is intended for systems where an external host systemwants to run an algorithm with raw data and this mode provides
new sample data every 250ms.
Note(s): Mode timings are subject to typical 2% tolerance due
to accuracy of internal clock

Early-Life Use (Burn-In)
CCS811 performance in terms of resistance levels andsensitivities will change during early life use. The change inresistance is greatest over the first 48 hours of operation. ams
advises customers to run CCS811 for 48 hours in the selectedmode of operation to ensure sensor performance is stable.

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CCS811 − Detailed Description

Conditioning Period (Run-In)
After early-life (Burn-In) period is complete the conditioning
period is the time required to achieve good sensor stability
before measuring VOCs after long idle period.
After writing to MEAS_MODE to configure the sensor in mode
1-4, run CCS811 for 20 minutes, before accurate readings are
generated.
The conditioning period must also be observed before writing
to the BASELINE register.

eCO 2
The equivalent CO 2 (eCO 2) output range for CCS811 is from400ppm to 8192ppm. Values outside this range are clipped.

TVOC
The Total Volatile Organic Compound (TVOC) output range for
CCS811 is from 0ppb to 1187ppb. Values outside this range areclipped.
This is calibrated to a typical TVOC mixture in an indoor
environment. If the ratio of compounds in the environment issignificantly different the TVOC output will be affected as some
VOC compounds will have greater or lesser effect on the sensor.

Temperature and Humidity Compensation
If an external sensor is available this information can be written
to CCS811 so that they will be used to compensate gas readings
due to temperature and humidity changes. Refer to the
ENV_DATA (Environment Data) Register (0x05).

Interrupt and Interrupt on Threshold
At the end of each measurement cycle (250ms, 1s, 10s, 60s) aflag is set and optionally interrupt (nINT) pin asserted. Refer tothe MEAS_MODE (Measurement and Conditions) Register(0x01). The user can choose to only assert nINT if the eCO 2 valuechanges into a different range set by register values. Refer to the
THRESHOLDS Register (0x10).

Optional NTC Circuit (AUX)CCS811 supports an external interface for connecting anegative thermal coefficient (NTC) thermistor to provide a costeffective and power efficient means of calculating the local
ambient temperature.
The thermistor enables the application to determine theambient temperature in the location where the CCS811 is
deployed. This temperature can subsequently be used forenvironmental compensation on the CCS811 MOX gas sensor.

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Page 9Document FeedbackCCS811 − Detailed Description

Refer to application note ams AN000372 for more details on
NTC configuration.
If an external temperature sensor is not available the external
NTC circuit can be used to determine the ambient temperature
and write this information to CCS811.
The NTC Register provides the voltages across the R NTC and the
R REF if fitted (mV) – to enable host system to calculate theambient temperature. The calculated temperature can be
written to CCS811 to compensate for gas changes due totemperature changes.

Automatic Baseline Correction
The resistance R S of the sensitive layer is the output of thesensor. However, metal oxide sensors do not give absolute
readings. The resistance R S varies from sensor to sensor(manufacturing variation), from use-case to use-case, and overtime. To mitigate this problem, the output of the sensor is
normalized: R S is divided by R A. The value of R A is known as thebaseline. R A cannot be determined by a one-time calibration; it
is maintained on-the-fly in software. This process is known asbaseline correction. The air quality is expected to vary in a
typical environment so the minimum time over which abaseline correction is applied is 24 hours.

Manual Baseline Correction
There is a mechanism within CCS811 to manually save andrestore a previously saved baseline value using the BASELINE
register.
The correct time to save the baseline will depend on thecustomer use-case and application.
• For devices which are powered for >24 hours at a time:• During the first 500 hours – save the baseline every
24-48 hours.
• After the first 500 hours – save the baseline every 5-7days.
• For devices which are powered <24 hours at a time:• If the device is run in, save the baseline before power
down• If multiple operating modes are used, a separate
baseline should be stored for each
• The baseline should only be restored when theresistance is stable (typically 20-30 minutes)• If changing from a low to high power mode (without
spending at least 10 minutes in idle), the sensor
resistance should be allowed to settle again before
restoring the baseline

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CCS811 − Detailed Description

Note(s):1.

If a value is written to the BASELINE register while thesensor is stabilising, the output of the TVOC and eCO 2
calculations may be higher than expected.

2. The baseline must be written after the conditioning
periodFor additional information on using the CCS811 please refer toapplication note ams AN000369: CCS811 Programming andInterfacing Guide.

ams Datasheet[v1-02] 2017-Mar-15

Page 11
Document FeedbackCCS811 − Application Information

The recommended application circuit for CCS811 is shown
below.

Application Information
Figure 8:
Recommended Application Circuit

VDD

4K7

4K7

Host
Processor

4K7

Part of hostsystem

4K7

VDD

CCS811
Digital VOC sensor
SCL

SCL

SDA

SDA

GPIOx

nWAKE

Reset

nReset4.7uF

Interrupt

PWM

nINT
ADDR

Sense

GND

Note(s):1. The PWM (Pin 4) and Sense (Pin 5) signals on CCS811 must be connected together.
2. A decoupling capacitor must be placed close to the supply pin VDD on the CCS811.
3. Pull-up resistors for SCL and SDA assumed will be part of host system.
4. If power is not an issue, nWake can be connected to ground if a spare GPIO is not available on the host processor.
5. ADDR must be connected to either VDD (logic 1) or ground (logic 0) depending on the required lsb of the CCS811’s I²C slave address.

Host System Software Requirements
1. The minimum level of driver support that a host systemneeds is read and write I²C transactions of data bytes
where the nWAKE pin is asserted at least tAWAKE before
the transaction and kept asserted throughout.
2. An Interrupt handler is also recommended to tell theapplication code that the device has asserted aninterrupt.

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CCS811 − Application Information

I²C Interface
I²C transactions require a register address to be selected(written) and followed by data, as described by the transaction
types in the subsections below. Each Register location
corresponds to a byte or multiple bytes.
Multiple reads or writes in a single sequence will be to or fromthe same location (the address does not increment).
Therefore, registers are sometimes referred to as mailboxes inthis document.

I²C Register Write
Figure 9:
I²C Register Write

Write, register address onlyS

SLAVE ADDRESSW ADATA(REG ADDR)A P

Write value to registerS

SLAVE ADDRESSW ADATA(REG ADDR)

A

DATA

A P

S

SLAVE ADDRESSW ADATA(REG ADDR)

A

DATA

A

Write multiple data
values to register(mailbox)

From master to slave

S

Start condition

W

Write

From slave to master

P

STOP condition

R

Read

A

DATA

A P

Acknowledge

As shown above, a transaction may be:• Single Byte to select a register address for subsequentread• Two Bytes to select a register address and write a byte toit, typically to set a single-byte register value• Multi-Bytes to select a register address and write several
bytes to it, typically to set multiple configuration bytes

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I²C Register Read
Figure 10:
I²C Register Read

Select and read register
value

Select and read registervalue, as single
transaction

Select and repeatedly
read multiple data
values from registerS

SLAVE ADDRESSW ADATA(REG ADDR)

A P(select register address)

S

SLAVE ADDRESS

R A

DATA

N P

(read register value)S

SLAVE ADDRESSW ADATA(REG ADDR)A SSLAVE ADDRESS(select register address)

R A

DATA

N P

(read register value)

A P(select register address)

S

SLAVE ADDRESSW ADATA(REG ADDR)SSLAVE ADDRESS

R A

DATA

A

DATA

N P

(read register multiple data)S

SLAVE ADDRESS

R A

DATA

A

DATA

N P

(read register multiple data)S

SLAVE ADDRESS

R A

DATA

A

DATA

N P

(read register multiple data)

From master to slave

S

Start condition

W

Write

A

Acknowledge

From slave to master

P

STOP condition

R

Read

N

Not acknowledge• Since no register address can be supplied during an I²C
read, an I²C write needs to be prepended to select therequired register first.
• The write and read operations can optionally be combined
into a single transaction using a repeated start condition,
as shown in the second example above.
• Select and repeatedly read multiple data values fromregister, if the three reads are from the same register(mailbox), or from three subsequent registers (mailboxes).

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CCS811 − Application Register Overview

Application Register Overview

All I²C transactions must use the (7 bits) slave address 0x5A or
0x5B depending on status of ADDR pin when writing to andreading from the CCS811. Figure 11 shows the register map for
CCS811. Figure 23 shows the bootloader register map.

Figure 11:
CCS811 Application Register Map

Address

Register

R/W

Size

Description

0x00

STATUSR

1 byteStatus register

0x01

MEAS_MODE

R/W

1 byteMeasurement mode and conditions register
Algorithm result. The most significant 2 bytes contain a
ppm estimate of the equivalent CO2 (eCO2) level, andthe next two bytes contain a ppb estimate of the total
VOC level.

0x02

ALG_RESULT_DATA

R

up to
8 bytes

0x03

RAW_DATAR

2 bytes

Raw ADC data values for resistance and current source
used.

0x05

ENV_DATAW

4 bytes

Temperature and humidity data can be written to
enable compensation

0x06

NTC

R

4 bytes

Provides the voltage across the reference resistor andthe voltage across the NTC resistor – from which theambient temperature can be determined.

0x10

THRESHOLDS

W

5 bytesThresholds for operation when interrupts are only
generated when eCO2 ppm crosses a threshold

0x11

BASELINE

R/W

2 bytes

The encoded current baseline value can be read. A
previously saved encoded baseline can be written.

0x20

HW_ID

R

1 byteHardware ID. The value is 0x81

0x21

HW Version

R

1 byteHardware Version. The value is 0x1X

0x23

FW_Boot_Version

R

2 bytes

Firmware Boot Version. The first 2 bytes contain thefirmware version number for the boot code.

0x24

FW_App_Version

R

2 bytes

Firmware Application Version. The first 2 bytes containthe firmware version number for the application code

0xE0

ERROR_IDR

1 byteError ID. When the status register reports an error its
source is located in this register

0xFF

SW_RESETW

4 bytes

If the correct 4 bytes (0x11 0xE5 0x72 0x8A) are written
to this register in a single sequence the device will reset
and return to BOOT mode.

Note(s):1. The number of bytes read from a register must not exceed the size in this table.
2. For more information on CCS811 programming requirements please refer to ams application note AN000369.

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Document FeedbackCCS811 − Application Register Overview

STATUS Register (0x00)
Single byte read only register which indicates if a device isactive, if new data is available or if an error occurred.
Figure 12:
Status Register
7

6

FW_MODE

5-

4

3

APP_VALIDDATA_READY

2

1
-

0
ERROR

Bit(s)

Field

7

FW_MODE

6:5-

4

APP_VALID

0: No application firmware loaded
1: Valid application firmware loaded3

DATA_READY

0: No new data samples are ready
1: A new data sample is ready in ALG_RESULT_DATA, this bit is cleared when
ALG_RESULT_DATA is read on the I²C interface

2:1

-

0

ERROR

Page 16Document Feedback

Description
0: Firmware is in boot mode, this allows new firmware to be loaded
1: Firmware is in application mode. CCS811 is ready to take ADC measurements
Reserved

Reserved
0: No error has occurred
1: There is an error on the I²C or sensor, the ERROR_ID register (0xE0) contains theerror source

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CCS811 − Application Register Overview

MEAS_MODE (Measurement and Conditions)Register (0x01)
This is Single byte register, which is used to enable sensor drivemode and interrupts.
Figure 13:
Measure Mode Register
7

6

-

4

DRIVE_MODE

Bit(s)

Field

7

-

6:4

5

DRIVE_MODE

3

2

INTERRUPTTHRESH

1

0-

Description
Reserved – write ‘0’000: Mode 0 – Idle (Measurements are disabled in this mode)
001: Mode 1 – Constant power mode, IAQ measurement every second
010: Mode 2 – Pulse heating mode IAQ measurement every 10 seconds
011: Mode 3 – Low power pulse heating mode IAQ measurement every 60
seconds
100: Mode 4 – Constant power mode, sensor measurement every 250ms
1xx: Reserved modes (For future use)
In mode 4, the ALG_RESULT_DATA is not updated, only RAW_DATA; the processing
must be done on the host system.
A new sample is placed in ALG_RESULT_DATA and RAW_DATA registers and the
DATA_READY bit in the STATUS register is set at the defined measurement interval.

3

INT_DATARDY

0: Interrupt generation is disabled
1: The nINT signal is asserted (driven low) when a new sample is ready in
ALG_RESULT_DATA. The nINT signal will stop being driven low when
ALG_RESULT_DATA is read on the I²C interface.
At the end of each measurement cycle (250ms, 1s, 10s, 60s) a flag is set in the
STATUS register regardless of the setting of this bit..

2

INT_THRESH

1:0-

ams Datasheet[v1-02] 2017-Mar-15

0: Interrupt mode (if enabled) operates normally
1: Interrupt mode (if enabled) only asserts the nINT signal (driven low) if the new
ALG_RESULT_DATA crosses one of the thresholds set in the THRESHOLDS registerby more than the hysteresis value (also in the THRESHOLDS register)
Reserved

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ALG_RESULT_DATA (Algorithm Results Data)
Register (0x02)
This multi-byte read only register contains the calculated eCO 2(ppm) and TVOC (ppb) values followed by the STATUS register,
ERROR_ID register and the RAW_DATA register.
• If only eCO 2 is required, only the first 2 bytes need to beread.
• If TVOC is required, 4 bytes need to be read.
• In a system where interrupts are not implemented and thehost needs to poll the STATUS register to determine
whether there is new data, an efficient alternative is toread 5 bytes in a single transaction since that returns eCO2,
TVOC and the status register.
• Optionally, all 8 bytes could be read in a single transaction,
so that even the error status and the raw data is available.
Figure 14:
Algorithm Results Register Byte Order

Byte 0

Byte 1

Byte 2Byte 3

Byte 4

Byte 5

Byte 6 & 7

eCO2 High Byte

eCO2 Low Byte

TVOC High Byte

TVOC Low Byte

STATUSERROR_ID

See RAW_DATA

RAW_DATA Register (0x03)
Two byte read only register which contains the latest readings
from the sense resistor.
The most significant 6 bits of the Byte 0 contain the value of thecurrent through the sensor (0μA to 63μA).
The lower 10 bits contain (as computed from the ADC) thereadings of the voltage across the sensor with the selectedcurrent (1023 = 1.65V)
Figure 15:
RAW_DATA Register Byte Order

Byte 0
7

6

5

4

3

Current Selected 5:0

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Document Feedback

Byte 1
2

1

0

7

6

5

4

3

2

1

0

Raw ADC reading 9:0

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CCS811 − Application Register Overview

ENV_DATA (Environment Data) Register (0x05)
A multi-byte register that can be written with the current
Humidity and Temperature values if known.

Relative Humidity
Figure 16:
Relative Humidity Fields and Byte Order

Byte 0

Byte 1

Humidity High Byte

Humidity Low Byte

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

64

32

16

8

4

2

1

1/2

1/4

1/8

1/16

1/32

1/64

1/128

1/256

1/512

Humidity %Humidity % Fraction
Humidity is stored as an unsigned 16 bits in 1/512%RH. The
default value is 50% = 0x64, 0x00. As an example 48.5%
humidity would be 0x61, 0x00.

Temperature
Figure 17:
Temperature Fields and Byte Order

Byte 2Byte 3Temperature High Byte

Temperature Low Byte

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

64

32

16

8

4

2

1

1/2

1/4

1/8

1/16

1/32

1/64

1/128

1/256

1/512

Temperature 25°C

Temperature 25°C Fraction
Temperature is stored as an unsigned 16 bits integer in 1/512
degrees; there is an offset: 0 maps to -25°C. The default value is
25°C = 0x64, 0x00. As an example 23.5% temperature would be
0x61, 0x00.
The internal algorithm uses these values (or default values if
not set by the application) to compensate for changes inrelative humidity and ambient temperature.

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NTC Register (0x06)
Four byte read only register which contains the voltage acrossresistor (R REF) and the voltage across the NTC resistor fromwhich the ambient temperature can be determined.
The resistance of the NTC resistor can be determined by theratio value and knowledge of the reference resistor used.
R NTC = VNTC x R REF / VREF. The temperature can be determinedfrom the resistance of the NTC resistor from the datasheet of
the NTC resistor used.
Figure 18:
NTC Register Byte Order

Byte 0

Byte 1

Byte 2

Voltage across RREF (mV)High Byte

Byte 3

Voltage across RNTC (mV)

Low Byte

High Byte

Low Byte

This enables the host to calculate the ambient temperature andthis information can be written to CCS811 to compensate fortemperature changes.

THRESHOLDS Register (0x10)
If ‘interrupt on threshold change’ has been set in the Moderegister (see above), the values in this multi- byte write only
register are used to determine the thresholds and the level ofhysteresis desired.
Figure 19:
Thresholds Register Byte Order

Byte 0

Byte 1

Low to Medium Threshold

Byte 2Byte 3

Byte 4

Medium to High Threshold
Hysteresis ValueHigh Byte

Low Byte

High Byte

Low Byte

An interrupt is asserted if the eCO 2 value moved from thecurrent range (Low, Medium, or High) into another range bymore than the Hysteresis value (used to prevent multiple
interrupts close to a threshold).
• Low to Medium Threshold default = 1500ppm = 0x05DC• Medium to High Threshold default = 2500ppm = 0x09C4• Hysteresis value default = 50 = 0x32

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Document Feedbackams Datasheet[v1-02] 2017-Mar-15

CCS811 − Application Register Overview

BASELINE Register (0x11)
A two byte read/write register which contains an encodedversion of the current baseline used in Algorithm Calculations.
A previously stored value may be written back to this two byte
register and the Algorithms will use the new value in its
calculations (until it adjusts it as part of its internal Automatic
Baseline Correction).

HW_ID (Hardware identifier) Register (0x20)
Single byte read only register which holds the HW ID which is
0x81 for this family of CCS81x devices.

HW_Version (Hardware Version) Register(0x21)
Single byte read only register which holds the Hardware Major
and Minor Hardware versions.
The top four bits read major hardware version 1 – identifying
the product as CCS811. The bottom four bits identify any build
variant. The default value is 0x1X.

FW_Boot_Version (Firmware Bootloader
Version) Register (0x23)
Two byte read only register which contain the version of thefirmware bootloader stored in the CCS811 in the format
Major.Minor.Trivial
Figure 20:
Firmware Bootloader Version Format

Byte 0
7

6

5

Major

ams Datasheet[v1-02] 2017-Mar-15

43

Byte 1
2

1

Minor

0

7

6

5

4

3

2

1

0

TrivialPage 21
Document FeedbackCCS811 − Application Register Overview

FW_App_Version (Firmware Application
Version) Register (0x24)
Two byte read only register which contain the version of thefirmware application stored in the CCS811 in the format
Major.Minor.Trivial
Figure 21:
Firmware Application Version Format

Byte 0
7

6

5

4

Major

3

Byte 1
2

1

0

7

6

5

Minor

4

3

2

1

0

TrivialERROR_ID (Error Identifier) Register (0xE0)
If the ERR bit [0] of the STATUS Register is set, this single byte
read only register indicates source(s) of the error.
Figure 22:
ERROR_ID Register Codes

Bit

ERROR_CODE

Description

0

WRITE_REG_INVALIDThe CCS811 received an I²C write request addressed to this station but withinvalid register address ID

1

READ_REG_INVALIDThe CCS811 received an I²C read request to a mailbox ID that is invalid

2

MEASMODE_INVALIDThe CCS811 received an I²C request to write an unsupported mode to
MEAS_MODE

3

MAX_RESISTANCE

The sensor resistance measurement has reached or exceeded the maximum
range

4

HEATER_FAULTThe Heater current in the CCS811 is not in range

5

HEATER_SUPPLYThe Heater voltage is not being applied correctly

6-

Reserved for Future Use

7-

Reserved for Future Use

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Document Feedbackams Datasheet[v1-02] 2017-Mar-15

CCS811 − Application Register Overview

SW_RESET Register (0xFF)
As an alternative to Power-On reset or Hardware Reset a
Software Reset is available.
Asserting the SW_RESET will restart the CCS811 in Boot mode
to enable new application firmware to be downloaded.
To prevent accidental SW_RESET a sequence of four bytes must
be written to this register in a single I²C sequence: 0x11, 0xE5,
0x72, 0x8A.
For details, please refer to application notes
ams AN000369 and ams AN000371.

ams Datasheet[v1-02] 2017-Mar-15

Page 23
Document FeedbackCCS811 − Bootloader Register Over view

Bootloader Register Overview

All I²C transactions must use the (7bits) slave address 0x5A or
0x5B depending on status of ADDR pin when writing to andreading from the CCS811. Figure 23 shows the bootloader
register map for CCS811.

Figure 23:
CCS811 Bootloader Register Map

Address

Register

R/W

Size

Description

0x00

STATUSR

1 byteStatus register

0x20

HW_ID

R

1 byteHardware ID. The value is 0x81

0x21

HW Version

R

1 byteHardware Version. The value is 0x1X

0x23

FW_Boot_Version

R

2 bytes

Firmware Boot Version. The first 2 bytes contain thefirmware version number for the boot code.

0x24

FW_App_Version

R

2 bytes

Firmware Application Version. The first 2 bytes containthe firmware version number for the application code.

0xE0

ERROR_IDR

1 byteError ID. When the status register reports an error it
source is located in this register

0xF1

APP_ERASE

W

4 bytes

If the correct 4 bytes (0xE7 0xA7 0xE6 0x09) are written
to this register in a single sequence the device will start
the application erase

0xF2

APP_DATAW

9 bytes

Transmit flash code for the bootloader to write to theapplication flash code space.

0xF3

APP_VERIFY

W-

Starts the process of the bootloader checking though
the application to make sure a full image is valid.

0xF4

APP_STARTW-

Application start. Used to transition the CCS811 statefrom boot to application mode, a write with no data isrequired. Before performing a write to APP_START the
Status register should be accessed to check if there is avalid application present.

0xFF

SW_RESETW

4 bytes

If the correct 4 bytes (0x11 0xE5 0x72 0x8A) are written
to this register in a single sequence the device will reset
and return to BOOT mode.

Note(s):1. The number of bytes read from a register must not exceed the size in this table.
2. For more information on performing application code download please refer to application note ams AN000371.

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Document Feedbackams Datasheet[v1-02] 2017-Mar-15

CCS811 − Bootloader Register Overview

Registers not detailed below are documented in the
Application Register Overview section.

APP_ERASE (Application Erase) Register (0xF1)
To prevent accidental APP_ERASE a sequence of four bytes must
be written to this register in a single I²C sequence: 0xE7, 0xA7,
0xE6, 0x09.
The APP_ERASE can take a variable amount of time. The status
register can be polled to determine when this function iscomplete. The 6 th bit (0x40) is initialised to 0 and set to a 1 oncompletion of the APP_ERASE function. After an erase this bit
is only cleared by doing a reset or starting the application.

APP_DATA (Application Data) Register (0xF2)
Nine byte, write only register for sending small chunks ofapplication data which will be written in order to the CCS811
flash code.

APP_VERIFY (Application Verify) Register(0xF3)
Single byte write only register which starts the application
verify process run by the bootloader to check for a complete
application code image. Command only needs to be called once
after a firmware download as the result is saved in a flash
location that gets checked during device initialisation.
The APP_VERIFY can take a variable amount of time. The status
register can be polled to determine when this function iscomplete. The 5 th bit (0x20) is initialised to 0 and set to a 1 oncompletion of the APP_VERIFY function. After an APP_VERIFY
this bit is only cleared by doing a reset or starting theapplication.
For details on downloading new application firmware pleaserefer to application note ams AN000371.

APP_START (Application Start) Register (0xF4)
To change the mode of the CCS811 from Boot mode to running
the application, a single byte write of 0xF4 is required.
The CCS811 interprets this as an address write to select the‘APP_START’ register and starts running the loaded application
software if it is a valid version (Refer to the STATUS Register(0x00)).

ams Datasheet[v1-02] 2017-Mar-15

Page 25
Document FeedbackCCS811 − Package Drawings & Mark ing

Package Drawings & Marking
LGA Package Outline
Figure 24:
LGA Package Drawings
Pin 1 Corner
Index Area

(Top View)(Side View)

D

A

E

1.2

nxL
nxW
6

5

e
D1

2.4

1

Pin 1 Corner
Index Area

RoHS

10

(0.3)

Green

E1
(Bottom View)

SymbolTotal thickness
Body Size
Lead Width
Lead Length
Lead Pitch
Lead Count
Edge Lead Centre to Centre

A
D
E
W
L
e
n
D1
E1

Min
-

0.25
0.45

Dimensions
Nominal
4.0
2.7
0.3
0.5
0.6
10
2.4
2.2

Max
1.1
BSC
BSC
0.35
0.55
BSC
BSC
BSC

Note(s):1. All dimensions are in millimeters.

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Document Feedbackams Datasheet[v1-02] 2017-Mar-15

CCS811 − Package Drawings & Marking

The recommended package footprint or landing pattern for
CCS811 is shown below:
Figure 25:
Recommended Package Footprint for CCS811

2.7
0.6

0.3

0.75
1

10

0.3

0.4

0.6
4

0.4

5

6

1.3

0.7

(Top View)
Note(s):1. All dimensions are in millimeters.
2. PCB land pattern in Green dash lines
3. Pin numbers are in Red
4. Add 0.05mm all around the nominal lead width and length for the PCB land patternams Datasheet[v1-02] 2017-Mar-15

Page 27
Document FeedbackCCS811 − Ordering & Contact Information

Ordering & Contact Information
Figure 26:
Ordering Information

Ordering CodeDescription

Package

MOQ

CCS811B-JOPR5K

CCS811 digital gas sensor for Indoor
Air Quality Monitoring

2.7mm x 4.0mm x 1.1mm LGA

5000

CCS811B-JOPD500

Sample of CCS811 digital gas sensor
for Indoor Air Quality Monitoring

2.7mm x 4.0mm x 1.1mm LGA

500

Note(s):
1. Refer to JEDEC J-STD020 lead-free standard for typical soldering reflow profile

Technical Support is available at:www.ams.com/Technical-Support
Provide feedback about this document at:
www.ams.com/Document-Feedback
For further information and requests, e-mail us at:
ams_sales@ams.com
For sales offices, distributors and representatives, please visit:www.ams.com/contact
Headquarters
ams AG
Tobelbader Strasse 30
8141 Premstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com

Page 28
Document Feedbackams Datasheet[v1-02] 2017-Mar-15

CCS811 − RoHS Compliant & ams Green Statement

RoHS Compliant & ams GreenStatement

RoHS: The term RoHS compliant means that ams AG products
fully comply with current RoHS directives. Our semiconductor
products do not contain any chemicals for all 6 substancecategories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed tobe soldered at high temperatures, RoHS compliant products are
suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br): ams Greendefines that in addition to RoHS compliance, our products arefree of Bromine (Br) and Antimony (Sb) based flame retardants(Br or Sb do not exceed 0.1% by weight in homogeneousmaterial).
Important Information: The information provided in thisstatement represents ams AG knowledge and belief as of thedate that it is provided. ams AG bases its knowledge and belief
on information provided by third parties, and makes norepresentation or warranty as to the accuracy of suchinformation. Efforts are underway to better integrate
information from third parties. ams AG has taken and continues
to take reasonable steps to provide representative and accurate
information but may not have conducted destructive testing or
chemical analysis on incoming materials and chemicals. ams AG
and ams AG suppliers consider certain information to be
proprietary, and thus CAS numbers and other limited
information may not be available for release.

ams Datasheet[v1-02] 2017-Mar-15

Page 29
Document FeedbackCCS811 − Copyrights & Disclaimer

Copyrights & Disclaimer

Copyright ams AG, Tobelbader Strasse 30, 8141 Premstaetten,
Austria-Europe. Trademarks Registered. All rights reserved. The
material herein may not be reproduced, adapted, merged,translated, stored, or used without the prior written consent of
the copyright owner.
Devices sold by ams AG are covered by the warranty and patentindemnification provisions appearing in its General Terms ofTrade. ams AG makes no warranty, express, statutory, implied,or by description regarding the information set forth herein.
ams AG reserves the right to change specifications and prices
at any time and without notice. Therefore, prior to designing
this product into a system, it is necessary to check with ams AG
for current information. This product is intended for use incommercial applications. Applications requiring extended
temperature range, unusual environmental requirements, orhigh reliability applications, such as military, medical
life-support or life-sustaining equipment are specifically notrecommended without additional processing by ams AG foreach application. This product is provided by ams AG “AS IS”
and any express or implied warranties, including, but notlimited to the implied warranties of merchantability and fitness
for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any
damages, including but not limited to personal injury, property
damage, loss of profits, loss of use, interruption of business orindirect, special, incidental or consequential damages, of any
kind, in connection with or arising out of the furnishing,performance or use of the technical data herein. No obligation
or liability to recipient or any third party shall arise or flow outof ams AG rendering of technical or other services.

Page 30
Document Feedbackams Datasheet[v1-02] 2017-Mar-15

CCS811 − Document Status

Document Status

Document Status

Product Preview

Preliminary Datasheet

Datasheet

Datasheet (discontinued)

ams Datasheet[v1-02] 2017-Mar-15

Product Status

Definition

Pre-Development

Information in this datasheet is based on product ideas in
the planning phase of development. All specifications aredesign goals without any warranty and are subject tochange without notice

Pre-Production

Information in this datasheet is based on products in thedesign, validation or qualification phase of development.
The performance and parameters shown in this document
are preliminary without any warranty and are subject tochange without notice

Production

Information in this datasheet is based on products in
ramp-up to full production or full production which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade

Discontinued

Information in this datasheet is based on products which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms ofTrade, but these products have been superseded andshould not be used for new designs

Page 31
Document FeedbackCCS811 − Revision Information

Revision Information

Changes from 1-00 (2016-Dec-23) to current revision 1-02 (2017-Mar-15)

Page

1-00 (2016-Dec-23) to 1-01 (2017-Feb-16)
Updated Figure 2

3

Updated Figure 4

4Updated Figure 8 and notes below

12

1-01 (2017-Feb-16) to 1-02 (2017-Mar-15)
Removed Product Marking information
Updated Figure 5

5Updated Figure 8 and notes under it

12Updated Figure 26

28

Note(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.

Page 32
Document Feedbackams Datasheet[v1-02] 2017-Mar-15

CCS811 − Appendix

Appendix
References
Figure 27:
Document Reference

Document Reference

Description

ams AN000367

Assembly guidelines for CCS811

ams AN000368

Mechanical considerations for CCS811

ams AN000369

CCS811 programming and interfacing guideams AN000370

CCS811 Clean Air Baseline Save and Restore

ams AN000371

CCS811 Performing a Firmware download

ams AN000372

Connecting an NTC Thermistor to the CCS811

ams AN000373

CCS811 Manufacture Test Procedure

ams WP000102

IAQ User experience during initial operation

ams Datasheet[v1-02] 2017-Mar-15

Page 33
Document FeedbackCCS811 − Content Guide

Content Guide

1
2
2
3

General Description
Key Benefits & Features
Applications
Block Diagram

4
5
6

Pin Assignment
Absolute Maximum Ratings
Electrical Characteristics

8
8
8
9
9
9
9
9
9
10
10

Detailed Description
Modes of Operation
Early-Life Use (Burn-In)
Conditioning Period (Run-In)
eCO2
TVOC
Temperature and Humidity Compensation
Interrupt and Interrupt on Threshold
Optional NTC Circuit (AUX)
Automatic Baseline Correction
Manual Baseline Correction

12
12
13
13
14

Application Information
Host System Software Requirements
I²C Interface
I²C Register Write
I²C Register Read

15
16
17

22
23

Application Register Overview
STATUS Register (0x00)
MEAS_MODE (Measurement and Conditions) Register(0x01)
ALG_RESULT_DATA (Algorithm Results Data) Register(0x02)
RAW_DATA Register (0x03)
ENV_DATA (Environment Data) Register (0x05)
Relative Humidity
NTC Register (0x06)
THRESHOLDS Register (0x10)
BASELINE Register (0x11)
HW_ID (Hardware identifier) Register (0x20)
HW_Version (Hardware Version) Register (0x21)
FW_Boot_Version (Firmware Bootloader Version) Register (0x23)
FW_App_Version (Firmware Application Version) Register (0x24)
ERROR_ID (Error Identifier) Register (0xE0)
SW_RESET Register (0xFF)

24
25
25
25
25

Bootloader Register Overview
APP_ERASE (Application Erase) Register (0xF1)
APP_DATA (Application Data) Register (0xF2)
APP_VERIFY (Application Verify) Register (0xF3)
APP_START (Application Start) Register (0xF4)

18
18
19
19
20
20
21
21
21
21
22

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CCS811 − Content Guide

ams Datasheet[v1-02] 2017-Mar-15

26
26

Package Drawings & Marking
LGA Package Outline

28
29
30
31
32

Ordering & Contact Information
RoHS Compliant & ams Green Statement
Copyrights & Disclaimer
Document Status
Revision Information

33
33

Appendix
References

Page 35
Document Feedback