AD7870A

a LC2MOS Complete, 12-Bit, 100 kHz , Sampling ADC AD7870A FUNCTIONAL BLOCK DIAGRAM FEATURES Complete Monolithic 12-Bit ADC with: 2 ␮s Track/Hold Amplifier 8 ␮s A/D Converter On-Chip Reference Laser-Trimmed Clock Parallel, Byte and Serial Digital Interface 70 dB SNR at 10 kHz Input Frequency 57 ns Data Access Time Low Power—60 mW typ APPLICATIONS Digital Signal Processing Speech Recognition and Synthesis Spectrum Analysis High Speed Modems DSP Servo Control GENERAL DESCRIPTION The AD7870A 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 that 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. AD7870A offers 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. The AD7870A operates from ± 5 V power supplies, accepts bipolar input signals of ± 3 V and can convert full power signals up to 50 kHz. In addition to the traditional dc accuracy specifications such as linearity, full-scale and offset errors, the AD7870A is also fully specified for dynamic performance parameters including harmonic dist...