The AD7715 is a complete analog front end for low frequency measurement applications. The part can accept low level input signals directly from a transducer and outputs a serial digital word. It employs a Σ-Δ conversion technique to realize up to 16 bits of no missing codes performance. The input signal is applied to a proprietary programmable gain front end based around an analog modulator. The modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via the on-chip control register allowing adjustment of the filter cutoff and output update rate. The AD7715 features a differential analog input as well as a differential reference input. It operates from a single supply （3 V or 5 V）。 It can handle unipolar input signal ranges of 0 mV to 20 mV， 0 mV to 80 mV， 0 V to 1.25 V and 0 V to 2.5 V. It can also handle bipolar input signal ranges of ±20 mV， ±80 mV， ±1.25 V and ±2.5 V. These bipolar ranges are referenced to the negative input of the differential analog input. The AD7715 thus performs all signal conditioning and conversion for a single channel system. The AD7715 is ideal for use in smart， microcontroller， or DSPbased systems. It features a serial interface that can be configured for three-wire operation. Gain settings， signal polarity， and update rate selection can be configured in software using the input serial port. The part contains self-calibration and system calibration options to eliminate gain and offset errors on the part itself or in the system.