AD7792BRUZ-REEL Data Converter IC ADC 3Ch Lo Noise Lo Pwr 16B w/ On-Chip Ref

FEATURES

• FUNCTIONAL BLOCK DIAGRAM

• 3-Channel, Low Noise, Low Power, 16-/24-Bit ∑-Δ ADC with On-Chip In-Amp and Reference

• Up to 23 bits effective resolution
• RMS noise
• 40 nV @ 4.17 Hz
• 85 nV @ 16.7 Hz AVDD Current: 400 μA typical
• AIN1(+)
• Power-down: 1 μA maximum AIN1(–) MUX AIN2(+)

• DOUT/RDY

• GND AVDD

• REFIN(+)/AIN3(+) REFIN(–)/AIN3(–)
• GND
• DIN ADC SCLK

• AD7792/AD7793

• Low noise programmable gain instrumentation amp AIN2(–) Band gap reference with 4 ppm/°C drift typical

• BUF

• IN-AMP Σ-Δ

• Update rate: 4.17 Hz to 470 Hz
• 3 differential inputs
• Internal clock oscillator Simultaneous 50 Hz/60 Hz rejection Programmable current sources On-chip bias voltage generator Burnout currents
• Power supply: 2.7 V to 5.25 V
• –40°C to +105°C temperature range Independent interface power supply 16-lead TSSOP package
• Interface
• 3-wire serial
• SPI®, QSPITM, MICROWIRETM, and DSP compatible Schmitt trigger on SCLK

APPLICATIONS

• Thermocouple measurements RTD measurements Thermistor measurements Gas analysis
• Industrial process control Instrumentation Portable instrumentation Blood analysis
• Smart transmitters Liquid/gas chromatography 6-digit DVM

GENERAL DESCRIPTION

The AD7792/AD7793 are low power, low noise, complete analog front ends for high precision measurement applications. The AD7792/AD7793 contain a low noise 16-/24-bit ∑-Δ ADC with three differential analog inputs. The on-chip, low noise instrumentation amplifier means that signals of small ampli- tude can be interfaced directly to the ADC. With a gain
setting of 64, the rms noise is 40 nV when the update rate equals 4.17 Hz.

The devices contain a precision low noise, low drift internal band gap reference and can accept an external differential reference. Other on-chip features include programmable excitation current sources, burnout currents, and a bias voltage generator. The bias voltage generator sets the common-mode voltage of a channel to AVDD/2.

The devices can be operated with either the internal clock or an external clock. The output data rate from the parts is software- programmable and can be varied from 4.17 Hz to 470 Hz.

The parts operate with a power supply from 2.7 V to 5.25 V. They consume a current of 400 μA typical and are housed in a 16-lead TSSOP package.