1 Features

1? Typical Values, TA = 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) 900-pA

(Maximum)

? Output Drive Current 750 μA

? Complete Potentiostat Circuit to Interface to Most

Not Biased Gas Sensors

? Low Bias Voltage Drift

? Programmable TIA Gain 2.75 kΩ to 350 kΩ

? I2C-Compatible Digital Interface

? Ambient Operating Temperature –40°C to 85°C

? Package 14-pin WSON

? Supported by Webench Sensor AFE Designer

2 Applications

? Gas Detectors

? Amperometric Applications

? Electrochemical Blood Glucose Meters

3 Description

The LMP91002 device 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 biased

gas sensor and a microcontroller generating an

output voltage proportional to the cell current.

The LMP91002’s programmability 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

5 μA to 750 μA full scale. The LMP91002’s

transimpedance amplifier (TIA) gain is programmable

through the I2C interface. The I2C interface can also be used for sensor diagnostics. The LMP91002 is

optimized for micro-power applications and operates

over a voltage range of 2.7 V to 3.6 V. The total

current consumption can be less than 10 μA. Further power savings are possible by switching off the TIA

amplifier and shorting the reference electrode to the working electrode with an internal switch.