1 Features
1• Typical Values, TA = 25°C
• Supply Voltage 2.7 V to 5.25 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 750 μA
• Complete Potentiostat Circuit-to-Interface to Most
Chemical Cells
• Programmable Cell Bias Voltage
• Low-Bias Voltage Drift
• Programmable TIA gain 2.75 kΩ to 350 kΩ
• Sink and Source Capability
• I2C Compatible Digital Interface
• Ambient Operating Temperature –40°C to 85°C
• Package 14-Pin WSON
• Supported by WEBENCH® Sensor AFE Designer

2 Applications
• Chemical Species Identification
• Amperometric Applications
• Electrochemical Blood Glucose Meter

3 Description
The LMP91000 is a programmable analog front-end
(AFE) for use in micro-power electrochemical sensing applications. It provides a complete signal path
solution between a sensor and a microcontroller that
generates an output voltage proportional to the cell
current. The LMP91000’s programmability enables it
to support multiple electrochemical sensors such as 3-lead toxic gas sensors and 2-lead galvanic cell
sensors with a single design as opposed to the
multiple discrete solutions. The LMP91000 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 LMP91000’s adjustable cell bias and transimpedance amplifier (TIA) gain are
programmable through the I2C interface. The I2C
interface can also be used for sensor diagnostics. An
integrated temperature sensor can be read by the user through the VOUT pin and used to provide
additional signal correction in the μC or monitored to
verify temperature conditions at the sensor.
The LMP91000 is optimized for micro-power applications and operates over a voltage range of 2.7
to 5.25 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.