Description

The AD7870 / AD7875 / AD7876 is a fast, complete, 12-bit A/D converter. It consists of a track/hold amplifier, 8 µs successive approximation ADC, 3 V buried Zener reference and versatile interface logic. The ADC features a self-contained internal clock which is laser trimmed to guarantee accurate control of conversion time. No external clock timing components are required; the on-chip clock may be overridden by an external clock if required.The parts offer a choice of three data output formats: a single, parallel, 12-bit word; two 8-bit bytes or serial data. Fast bus access times and standard control inputs ensure easy interfacing to modern microprocessors and digital signal processors.All parts operate from ±5 V power supplies. The AD7870 and AD7876 accept input signal ranges of ±3 V and ±10 V, respectively, while the AD7875 accepts a unipolar 0 V to +5 V input range. The parts can convert full power signals up to 50 kHz.The AD7870 / AD7875 / AD7876 feature dc accuracy specifications such as linearity, full-scale and offset error. In addition, the AD7870 and AD7875 are fully specified for dynamic performance parameters including distortion and signal-to-noise ratio.The parts are available in a 24-pin, 0.3 inch-wide, plastic or hermeticdual-in-line package (DIP). The AD7870 and AD7875 are available in a 28-pin plastic leaded chip carrier (PLCC), while the AD7876 is available and in a 24-pin small outline (SOIC) package.