I2C INTERFACE

AND

CONTROL

REGISTERS

RE

VREF

VDD

AGND

CE

WE

VOUT

C1

SCL

VREF

DIVIDER

C2

SDA

RLoad

DIAGNOSTIC

MENB

DGND

A1

+

-

TIA

+

-

RTIA

CE

WE

RE

3-Lead

Electrochemical

Cell

MSP430

LMP91002

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LMP91002

SNIS163B – APRIL 2012 – REVISED OCTOBER 2015

LMP91002 Sensor AFE System: Configurable AFE Potentiostat for Low-Power Chemical

Sensing Applications

1 Features

3 Description

The LMP91002 device is a programmable Analog

1

•

Typical Values, TA = 25°C

Front

End

(AFE)

for

use

in

micro-power

•

Supply Voltage 2.7 V to 3.6 V

electrochemical-sensing applications. It provides a

•

Supply Current (Average Over Time) < 10 µA

complete signal path solution between a not biased

gas sensor and a microcontroller generating an

•

Cell Conditioning Current Up to 10 mA

output voltage proportional to the cell current.

•

Reference Electrode Bias Current (85°C) 900-pA

(Maximum)

The LMP91002’s programmability enables it support

not biased electro-chemical gas sensor with a single

•

Output Drive Current 750 µA

design. The LMP91002 supports gas sensitivities

•

Complete Potentiostat Circuit to Interface to Most

over a range of 0.5 nA/ppm to 9500 nA/ppm. It also

Not Biased Gas Sensors

allows for an easy conversion of current ranges from

•

Low Bias Voltage Drift

5

μA to 750 μA full scale. The LMP91002’s

transimpedance amplifier (TIA) gain is programmable

•

Programmable TIA Gain 2.75 k

Ω to 350 kΩ

through the I2C interface. The I2C interface can also

•

I2C-Compatible Digital Interface

be used for sensor diagnostics. The LMP91002 is

•

Ambient Operating Temperature –40°C to 85°C

optimized for micro-power applications and operates

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

•

Package 14-pin WSON

current consumption can be less than 10

μA. Further

•

Supported by Webench Sensor AFE Designer

power savings are possible by switching off the TIA

amplifier and shorting the reference electrode to the

2 Applications

working electrode with an internal switch.

•

Gas Detectors

Device Information(1)

•

Amperometric Applications

PART NUMBER

PACKAGE

BODY SIZE (NOM)

•

Electrochemical Blood Glucose Meters

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

1

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.