GENERAL DESCRIPTION
The AD7794/AD7795 are low power, low noise, complete analog front ends for high precision measurement applications. They contain a low noise, 24-/16-bit ∑-Δ ADC with six differential inputs. The on-chip low noise instrumentation amplifier means that signals of small amplitude can be interfaced directly to the ADC.
FEATURES
Up to 23 effective bits
RMS noise: 40 nV @ 4.17 Hz, 85 nV @ 16.7 Hz
Current: 400 μA typical
Power-down: 1 μA maximum
Low noise, programmable gain, instrumentation amp
Band gap reference with 4 ppm/°C drift typical
Update rate: 4.17 Hz to 470 Hz
Six differential analog inputs
Internal clock oscillator
Simultaneous 50 Hz/60 Hz rejection
Reference detect
Programmable current sources
On-chip bias voltage generator
Burnout currents
Low-side power switch
Power supply: 2.7 V to 5.25 V
Temperature range:
B grade: –40°C to +105°C
C grade: –40°C to +125°C
Independent interface power supply
24-lead TSSOP
3-wire serial interface
SPI®, QSPI™, MICROWIRE™, and DSP compatible
Schmitt trigger on SCLK
APPLICATIONS
Temperature measurement
Pressure measurement
Weigh scales
Strain gage transducers
Gas analysis