AD7793 Datasheet | Analog Devices

.. Preliminary Technical Data Features Resolution: Low Power, 16/24-Bit Sigma-Delta ADC with Low-Noise In-Amp and Embedded Reference AD7792/AD7793 GND VBIAS VDD BANDGAP REFERENCE AVDD REFIN(+)/AIN3(+) REFIN(-)/AIN3(-) GND SIGMA DELTA ADC SERIAL INTERFACE AND CONTROL LOGIC DOUT/RDY DIN SCLK CS AIN1(+) AIN1(-) AIN2(+) AIN2(-) VDD IOUT1 IOUT2 GND INTERNAL CLOCK MUX IN-AMP AD7792: 16-Bit AD7793: 24-Bit Low Noise Programmable Gain Instrumentation-Amp RMS noise: 80 n V (Gain = 64) Bandgap Reference with 5ppm/ C Drift typ Power Supply: 2.7 V to 5.25 V operation Normal: 400 µA typ Power-down: 1 µA max Update Rate: 4 Hz to 500 Hz Simultaneous 50 Hz/60 Hz Rejection Internal Clock Oscillator Programmable Current Sources (10 µA/200 µA/1 m A) On-Chip Bias Voltage Generator 100 n A Burnout Currents Independent Interface Power Supply 16-Lead TSSOP Package DVDD AD7792/AD7793 Figure 1. GENERAL DESCRIPTION The AD7792/AD7793 is a low power, plete analog front end for low frequency measurement applications. The AD7792/AD7793 contains a low noise 16/24-bit ∑-∆ 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 80 n V when the update rate equals 16.6 Hz. The device contains a precision low noise, low drift internal bandgap reference for absolute measurements. An external reference can also be used if ratiometric measurements are required. On-chip programmable excitation current sources can be used to supply a constant current to RTDs and thermistors while the 100 n A burnout currents can be used to ensure that the sensors connected to the ADC are not burnt out. For thermocouple applications, the on-chip bias voltage generator steps up the mon mode voltage from the thermocouple so that it is within the ADC’s allowable range. The device can be operated with the internal clock or, alternatively, an...