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 amplitude 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 softwareprogrammable 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.