LMP91050_15 Datasheet, PDF (1/28 Pages) Texas Instruments – Configurable AFE for Nondispersive Infrared (NDIR) Sensing Applications

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LMP91050
SNAS517E – NOVEMBER 2011 – REVISED SEPTEMBER 2015
LMP91050 Configurable AFE for Nondispersive Infrared (NDIR) Sensing Applications
1 Features
•1 Programmable Gain Amplifier
• Dark Signal Offset Cancellation
• Supports External Filtering
• Common-Mode Generator and 8-Bit DAC
• Key Specifications
– Programmable Gain 167 to 7986 V/V
– Low Noise (0.1 to 10 Hz) 0.1 μVRMS
– Gain Drift 100 ppm/°C (Maximum)
– Phase Delay Drift 500 ns (Maximum)
– Power Supply Voltage Range 2.7 to 5.5 V
2 Applications
• NDIR Sensing
• Demand Control Ventilation
• Building Monitoring
• CO2 Cabin Control — Automotive
• Alcohol Detection — Automotive
• Industrial Safety and Security
• GHG and Freons Detection Platforms
3 Description
The LMP91050 device is a programmable integrated
Sensor Analog Front End (AFE) optimized for
thermopile sensors, as typically used in NDIR
applications. It provides a complete signal path
solution between a sensor and microcontroller that
generates an output voltage proportional to the
thermopile voltage. The programmability of the
LMP91050 enables it to support multiple thermopile
sensors with a single design as opposed to the
multiple discrete solutions.
The LMP91050 features a programmable gain
amplifier (PGA), dark phase offset cancellation, and
an adjustable common-mode generator (1.15 V or
2.59 V) which increases output dynamic range. The
PGA offers a low-gain range of 167 V/V to 1335 V/V
plus a high-gain range of 1002 V/V to 7986 V/V which
enables the user to use thermopiles with different
sensitivities. The PGA is highlighted by low-gain drift
(100 ppm/°C), output offset drift (1.2 mV/°C at G =
1002 V/V), phase delay drift (500 ns) and noise
specifications (0.1 μV_RMS 0.1 to 10Hz).
Device Information⁽¹⁾
PART NUMBER
PACKAGE
BODY SIZE (NOM)
LMP91050
VSSOP (10)
3.00 mm × 3.00 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application Circuit
10 µF 160 k
VDD
160 k
6.8 nF
10 µF
10 nF
VDD
Thermopile
IN
10 nF
CMOUT
10 nF
CMOUT
A0
A1
LMP91050
GND
OUT _{1 kO}
1 µF
CSB
SCLK
SDIO
û ADC
Configurable AFE for NDIR
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.