AD7793BRUZ-REEL

The AD7792/AD7793 are low power, low noise, complete analog front ends for high precision measurement applications. They incorporate a low noise, 16-bit/24-bit Σ-Δ ADC with three differential analog inputs. An on-chip low noise instrumentation amplifier enables direct interfacing to small signal inputs. At a gain of 64 and an update rate of 4.17 Hz, the RMS noise is 40 nV. Both devices include an on-chip precision, low noise, low drift internal bandgap reference, and an external differential reference can also be used. Additional on-chip features include programmable excitation current sources, burnout current sources, and a bias voltage generator. The bias voltage generator is used to set the common-mode voltage of the channel to AVDD/2. The devices can operate with an internal or external clock, and the output data rate is software programmable over a range of 4.17 Hz to 470 Hz. The devices operate from a 2.7 V to 5.25 V supply, with a typical current consumption of 400 μA, and are available in a 16-lead TSSOP package.

Applications

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

Key features

• Up to 23-bit effective resolution
• RMS noise: 40 nV (at 4.17 Hz); 85 nV (at 16.7 Hz)
• Current: 400 μA (typical)
• Power-down mode: 1 μA (maximum)
• Low-noise programmable gain instrumentation amplifier
• Bandgap voltage reference with typical temperature coefficient of 4 ppm/°C
• Update rate: 4.17 Hz to 470 Hz
• 3 differential inputs
• Internal clock oscillator
• Simultaneous 50 Hz/60 Hz rejection
• Programmable current source
• On-chip bias voltage generator
• Burnout current
• Supply voltage: 2.7 V to 5.25 V
• Temperature range: -40 °C to +105 °C
• Independent interface supply
• 16-lead TSSOP package
• Interface: 3-wire serial interface, SPI, QSPI, MICROWIRE, and DSP compatible, Schmitt trigger on SCLK pin