Datasheet

µC
SCL
SDA
GPIO 1
GPIO 2
GPIO N
SMART SENSOR AFE
LMP91000
SDA
SCL
I
2
C EEPROM
SDA
SCL
A0
MENB
LMP91000
SDA
SCL
I
2
C EEPROM
SDA
SCL
A0
MENB
SMART SENSOR AFE SMART SENSOR AFE
LMP91000
SDA
SCL
I
2
C EEPROM
SDA
SCL
A0
MENB
LMP91000
www.ti.com SNAS506H –JANUARY 2011–REVISED MARCH 2013
Figure 34. Smart Gas Sensor AFEs on I
2
C bus
POWER CONSUMPTION
The LMP91000 is intended for use in portable devices, so the power consumption is as low as possible in order
to guarantee a long battery life. The total power consumption for the LMP91000 is below 10µA at 3.3v average
over time, (this excludes any current drawn from any pin). A typical usage of the LMP91000 is in a portable gas
detector and its power consumption is summarized in Table 3. This has the following assumptions:
• Power On only happens a few times over life, so its power consumption can be ignored.
• Deep Sleep mode is not used.
• The system is used about 8 hours a day, and 16 hours a day it is in Standby mode.
• Temperature Measurement is done about once per minute.
This results in an average power consumption of approximately 7.95 µA. This can potentially be further reduced,
by using the Standby mode between gas measurements. It may even be possible, depending on the sensor
used, to go into deep sleep for some time between measurements, further reducing the average power
consumption.
Table 3. Power Consumption Scenario
3-Lead Temperature Temperature
Deep Sleep StandBy Amperometric Measurement Measurement Total
Cell TIA OFF TIA ON
Current consumption
(µA)
typical value 0.6 6.5 10 11.4 14.9
Time ON
(%) 0 60 39 0 1
Average
(µA) 0 3.9 3.9 0 0.15 7.95
Notes
A1 OFF ON ON ON ON
TIA OFF OFF ON OFF ON
TEMP SENSOR OFF OFF OFF ON ON
I
2
C interface ON ON ON ON ON
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