LMP91000 Datasheet, PDF (1/30 Pages) National Semiconductor (TI) – Sensor AFE System: Configurable AFE Potentiostat for Low-Power Chemical Sensing Applications

LMP91000
www.ti.com
SNAS506H – JANUARY 2011 – REVISED MARCH 2013
LMP91000 Sensor AFE System: Configurable AFE Potentiostat for Low-Power Chemical
Sensing Applications
Check for Samples: LMP91000
FEATURES
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•23 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 750µA
• Complete Potentiostat Circuit to Interface to
Most Chemical Cells
• Programmable Cell Bias Voltage
• Low Bias Voltage Drift
• Programmable TIA gain 2.75kΩ to 350kΩ
• 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
APPLICATIONS
• Chemical Species Identification
• Amperometric Applications
• Electrochemical Blood Glucose Meter
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 5µA to 750µA 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
2.7V to 5.25V. The total current consumption can be
less than 10μA. Further power savings are possible
by switching off the TIA amplifier and shorting the
reference electrode to the working electrode with an
internal switch.
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
WEBENCH is a registered trademark of Texas Instruments.
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All other trademarks are the property of their respective owners.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2011–2013, Texas Instruments Incorporated