LMP90097 - 24-Bit Sensor AFE with True Continuous Background Calibration

The LMP90xxx is a highly integrated, multichannel, low-power, 24-bit Sensor AFEs. The devices features a precision, 24-bit Sigma-Delta analog-to-digital converter (ADC) with a low-noise programmable gain amplifier and a fully differential high-impedance analog input multiplexer. A true continuous background calibration feature allows calibration at all gains and output data rates without interrupting the signal path. The background calibration feature essentially eliminates gain and offset errors across temperature and time, providing measurement accuracy without sacrificing speed and power consumption.

Another feature of the LMP90100/LMP90099/LMP90098/LMP90097 is continuous background sensor diagnostics, allowing the detection of open and short-circuit conditions and out-of-range signals, without requiring user intervention, resulting in enhanced system reliability.

Two sets of independent external reference voltage pins allow multiple ratiometric measurements. In addition, two matched programmable current sources are available in the LMP90100/LMP90098 to excite external sensors such as resistive temperature detectors and bridge sensors. Furthermore, seven GPIO pins are provided for interfacing to external LEDs and switches to simplify control across an isolation barrier.

Collectively, these features make the LMP90100/LMP90099/LMP90098/LMP90097 complete analog front-ends for low-power, precision sensor applications such as temperature, pressure, strain gauge, and industrial process control. The LMP90100/LMP90099/LMP90098/LMP90097 are ensured over the extended temperature range of –40°C to +125°C and are available in a 28-pin HTSSOP package with an exposed pad.

• 24-Bit, Low-Power Sigma-Delta ADC
• True Continuous Background Calibration at all
  Gains
• In-Place System Calibration Using Expected
  Value Programming
• Low-Noise Programmable Gain (1x to 128x)
• Continuous Background Open / Short and Out-of-
  Range Sensor Diagnostics
• 8 Output Data Rates (ODR) With Single-Cycle
  Settling
• 2 Matched Excitation Current Sources From 100
  µA to 1000 µA (LMP90100/LMP90098)
• 4-DIFF / 7-SE Inputs (LMP90100/LMP90099)
• 2-DIFF / 4-SE Inputs (LMP90098/LMP90097)
• 7 General-Purpose Input/Output Pins
• Chopper-Stabilized Buffer for Low Offset
• SPI 4/3-wire With CRC Data Link Error Detection
• 50-Hz to 60-Hz Line Rejection at ODR
  ≤13.42 SPS
• Independent Gain and ODR Selection per
  Channel
• Supported by WEBENCHR Sensor AFE Designer
• Automatic Channel Sequencer
• Key Specifications
  • ENOB/NFR Up to 21.5/19 Bits
  • Offset Error (Typical) 8.4 nV
  • Gain Error (Typical) 7 ppm
  • Total Noise < 10 µV-rms
  • Integral Nonlinearity (INL Maximum) ± 15 ppm
    of FSR
  • Output Data Rates (ODR) 1.6775 - 214.65
    SPS
  • Analog Voltage, VA 2.85 to 5.5 V
  • Operating Temp Range –4°C to 125°C
  • 28-Pin HTSSOP Exposed Pad