1 Features

1• High accuracy, low noise, low power, small size

resistive sensing signal conditioner

• User-programmable temperature and nonlinearity

compensation

• On-chip ARM® Cortex® M0 microprocessor allows

users to develop and implement calibration

software

• One-wire interface enables the communication

through power supply pin without using additional

lines

• On-chip power management accepts wide power

supply voltage from 3.3 V to 30 V

• Operating temperature range: –40°C to +150°C

• Memory:

– 8-kB software memory

– 128 bytes EEPROM

– 1-kB data SRAM

• Accommodates sensor sensitivities from 1 mV/V

to 135 mV/V

• Two individual analog-front end (AFE) chains,

each including:

– Low-noise programmable gain amplifier

– 24-bit sigma-delta analog-to-digital converter

• Built-in internal temperature sensor with option to

use external temperature sensor

• 14-bit DAC with programmable gain amplifier

• Output options:

– Ratiometric and absolute voltage output

– 4- to 20-mA current loop interface

– One-wire interface (OWI) over power line

– PWM output

– Serial peripheral interface (SPI)

– Inter-integrated circuit (I2C)

• Depletion MOSFET gate driver

• Diagnostic functions

2 Applications

• Pressure sensor transmitters and transducers

• Liquid level meters and flow meters

• Weight scales, load meters, and strain gauges

• Thermocouples, thermistors, and 2-wire

resistance thermometers (RTD)

• Resistive field transmitters

3 Description

The PGA900 is a signal conditioner for resistive

sensing applications. It can accommodate various

sensing element types. The PGA900 conditions its

input signals by amplification and digitization through

two analog front end channels. With the user

programmed software in the on-chip ARM Cortex M0

processor, the PGA900 can perform linearization,

temperature compensation, and other user defined

compensation algorithms. The conditioned signal can

be output as ratiometric voltage, absolute voltage, 4-

to 20-mA current loop or PWM. The data and

configuration registers can also be accessed through

SPI, I2C, UART, and two GPIO ports. In addition, the

unique OWI allows communication and configuration

through the power supply pin without using additional

lines. The PGA900 operating voltage is from 3.3 V to

30 V and it can operate in temperatures from –40°C

to +150°C.