AD7870

FEATURES Complete monolithic 12-bit ADCs with 2 μs track-and-hold amplifier 8 μs ADC On-chip reference Laser-trimmed clock Parallel, byte, and serial digital interface 72 dB SNR at 10 kHz input frequency (AD7870, AD7875) 57 ns data access time Low power: −60 mW typical Variety of input ranges ±3 V for AD7870 0 V to +5 V for AD7875 ±10 V for AD7876 GENERAL DESCRIPTION The AD7870/AD7875/AD7876 are fast, complete, 12-bit analog-to-digital converters (ADCs). These converters consist of a track-and-hold amplifier, an 8 μs successive approximation ADC, a 3 V buried Zener reference, and versatile interface logic. The ADCs feature 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 ful...