LMP91002 Datasheet, PDF (1/21 Pages) Texas Instruments – Sensor AFE System: Configurable AFE Potentiostat

LMP91002
April 24, 2012
Sensor AFE System: Configurable AFE Potentiostat for
Low-Power Chemical Sensing Applications
General Description
The LMP91002 is a programmable Analog Front End (AFE)
for use in micro-power electrochemical sensing applications.
It provides a complete signal path solution between a not bi-
ased gas sensor and a microcontroller generating an output
voltage proportional to the cell current. The LMP91002’s pro-
grammability enables it support not biased electro-chemical
gas sensor with a single design. The LMP91002 supports gas
sensitivities over a range of 0.5 nA/ppm to 9500 nA/ppm. It
also allows for an easy conversion of current ranges from
5μA to 750μA full scale. The LMP91002’s transimpedance
amplifier (TIA) gain is programmable through the I2C inter-
face. The I2C interface can also be used for sensor diagnos-
tics. The LMP91002 is optimized for micro-power applications
and operates over a voltage range of 2.7V to 3.6V. The total
current consumption can be less than 10μA. Further power
savings are possible by switching off the TIA amplifier and
shorting the reference electrode to the working electrode with
an internal switch.
Features
Typical Values, T_A = 25°C
■ ^{Supply voltage}
2.7 V to 3.6 V
■ ^{Supply current (average over time)}
<10 µA
■ ^{Cell conditioning current up to}
10 mA
■ ^{Reference electrode bias current (85°C) 900pA (max)}
■ ^{Output drive current}
750µA
■ ^{Complete potentiostat circuit to interface to most not bi-}
ased gas sensors
■ ^{Low bias voltage drift}
■ ^{Programmable TIA gain}
2.75kΩ to 350kΩ
■ ^{I2C compatible digital interface}
■ ^{Ambient operating temperature}
-40°C to 85°C
■ ^Package
14 pin LLP
■ ^{Supported by Webench Sensor AFE Designer}
Applications
■ ^{Gas detector}
■ ^{Amperometric applications}
■ ^{Electrochemical blood glucose meter}
Typical Application
AFE Gas Detector
© 2012 Texas Instruments Incorporated 301825 SNIS163
30182505
www.ti.com