Data Sheet

Page 8 ams Datasheet
Document Feedback [v1-00] 2016-Dec-23
CCS811 − 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) and
TVOC 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 the
lowest average operating current.
When a sensor operating mode is changed to a new mode with
a lower sample rate (e.g. from Mode 1 to Mode 3), it should be
placed 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 Mode
1), there is no requirement to wait before enabling the new
mode.
Mode 4 is intended for systems where an external host system
wants 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 and
sensitivities will change during early life use. The change in
resistance is greatest over the first 48 hours of operation. ams
advises customers to run CCS811 for 48 hours in the selected
mode of operation to ensure sensor performance is stable.
Detailed Description