1 Features
1• Analog features
– Programmable-gain analog front end for LVDT
sensors
– Excitation waveform generator and amplifier
– Dual 24-bit ADC with amplitude and phase
demodulators
– 24-bit auxilary ADC
– On-chip internal temperature sensor
– 14-bit output DAC with programmable gain
– Built-in diagnostics
• Digital features
– ARM® Cortex®-M0 microcontroller
– 16KB ferroelectric RAM (FRAM) program
memory
– 2KB general-pupose RAM
– 512B RAM waveform-generator look-up table
– 8-MHz on-chip oscillator
• Peripheral features
– Serial peripheral interface (SPI)
– One-wire interface (OWI)
– Ratiometric and absolute voltage output
• General features
– Operational supply range: 3.5 V to 30 V
– Ambient temperature range: –40°C to +125°C
– DMOS gate controller for extended supply
range >30 V

2 Applications
• Position sensor signal conditioning
• Linear variable differential transformer (LVDT)
• Rotational variable differential transformer (RVDT)
• Resolver
• RLC measurement

3 Description
The PGA970 is a highly integrated system-on-chip
LVDT sensor-signal conditioner with advanced signalprocessing
capabilities. It contains a three-channel,
low-noise, programmable-gain, analog front end that
allows direct connection to the sense element,
followed by three independent 24-bit delta-sigma
ADCs.
Further, the device contains a digital signaldemodulation
block that interfaces to an integrated
ARM-Cortex M0 MCU, allowing implementation of
custom sensor-compensation algorithms stored in the
device nonvolatile memory. External system
communication is achieved by using any of the SPI,
OWI, GPIO, or PWM digital interfaces. Analog output
is supported through a 14-bit DAC and
programmable-gain amplifier offering reference or
absolute-voltage output. Sensing-element excitation
is achieved by the use of an integrated waveform
generator and waveform amplifier. The waveform
signal data is user-defined and stored in a designated
RAM memory area.
Besides the primary functional components, the
PGA970 is equipped with additional support circuitry.
The device diagnostics, sensor diagnostics, and
integrated temperature sensor provide protection and
information about the integrity of the overall system
and sensing element. The device also includes a
gate-controller circuit which when used with an
external depletion MOSFET can regulate the device
supply voltage in systems where the supply voltage
exceeds 30 V.