LMP91000SDX/NOPB

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.

Key Features

• Typical Values, T_A = 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