SNIS163B April   2012  – October 2015 LMP91002

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 I2C Interface
    7. 6.7 Timing Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Potentiostat Circuitry
      2. 7.3.2 Transimpedance Amplifier
      3. 7.3.3 Control Amplifier
      4. 7.3.4 Internal Zero
      5. 7.3.5 2-Lead Galvanic Cell in Potentiostat Configuration
    4. 7.4 Device Functional Modes
      1. 7.4.1 Timeout Feature
    5. 7.5 Programming
      1. 7.5.1 I2C Interface
      2. 7.5.2 Write and Read Operation
      3. 7.5.3 Connection of More Than One LMP91002 to the I2C Bus
    6. 7.6 Register Maps
      1. 7.6.1 STATUS Register (Offset = 00h)
      2. 7.6.2 LOCK Register (Offset = 01h)
      3. 7.6.3 TIACN Register (Offset = 10h)
      4. 7.6.4 REFCN Register (Offset = 11h)
      5. 7.6.5 MODECN Register (Offset = 12h)
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Gas Sensor Interface
        1. 8.1.1.1 3-Lead Amperometric Cell In Potentiostat Configuration
      2. 8.1.2 Sensor Test Procedure
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Smart Gas Sensor Analog Front End
        2. 8.2.2.2 Smart Gas Sensor AFES on I2C Bus
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Power Consumption
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Community Resources
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

1 Features

  • 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.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LMP91002 WSON (14) 4.00 mm × 4.00 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application

LMP91002 30182505.gif