AD7785 Datasheet | Analog Devices

3-Channel, Low Noise, Low Power, 20-Bit ∑-Δ ADC with On-Chip In-Amp and Reference Features Up to 20 bits effective resolution RMS noise 40 n V @ 4.17 Hz 85 n V @ 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 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®, QSPI™, MICROWIRE™, and DSP patible Schmitt trigger on SCLK Industrial process control Instrumentation Portable instrumentation Blood analysis Smart transmitters Liquid/gas chromatography 6-digit DVM GENERAL DESCRIPTION The AD7785 is a low power, low noise, plete analog front end for high precision measurement applications. The AD7785 contains a low noise 20-bit ∑-Δ ADC with three differential analog inputs. The on-chip, low noise instrumentation amplifier means that signals of small amplitude can be interfaced directly to the ADC. With a gain setting of 64, the rms noise is 40 n V when the update rate equals 4.17 Hz. The device contains 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 mon-mode voltage of a channel to AVDD/2. The AD7785 can be operated with either the internal clock or an external clock. The output data rate from the device is software-programmable and can be varied from 4.17 Hz to 470 Hz. The device operates with a power supply from 2.7 V to 5.25 V. It consumes a current of 400 μA typical and is housed in a 16-lead TSSOP package. APPLICATIONS Thermocouple...