User Manual EE895
Miniature Sensor Module for CO
2
, Temperature and Barometric Pressure | 11
Example:
Fig. 7
Example UART interface
3.6 Electrical Characteristics
A DC/DC converter is used to flash the lamp (VCC_EM). Therefore, the supply current is reduced with higher
voltage and vice versa. The microcontroller (VCC_IO) is supplied via a linear reglator, hence the supply current is
constant.
The average current consumption at a sampling interval of 15 s (factory default) is 1.6 mA. Tab. 5 lists the typical
and maximum current values in each individual state during the sampling interval, which is shown in the current
Power Supply VCC_IO
VCC_EM
Status
3.3 V
5 V
Idle measurement
6.2 (9.9) mA
<0.1 µA
<0.1 µA
IR lamp pulse
6.2 (9.9) mA
85 (95) mA
60 (66) mA
Standby
190 (300) µA
<0.1 µA
<0.1 µA
Power off
<2 µA
<0.1 µA
<0.1 µA
Tab. 5
Current values in the individual measurement states, typ. (max.)
0
IR lamp pulse
Standby / power off
300 ms
300 ms
Idle
measurement
Sampling intervall 15 s (configurable 10 s ... 1 h)
Fig. 8
States during a CO
2
sampling interval
Further electrical characteristics:
Signal
Unit
Min
Max
Note
Clock frequency
Hz
500
100 000
Pull-up resistor
kΩ
4.7
100
Typical 10 kΩ
Tab. 6
Electrical characteristics
