AD7878

a LC2MOS Complete 12-Bit 100 kHz Sampling ADC with DSP Interface AD7878 FUNCTIONAL BLOCK DIAGRAM FEATURES Complete ADC with DSP Interface, Comprising: Track/Hold Amplifier with 2 ␮s Acquisition Time 7 ␮s A/D Converter 3 V Zener Reference 8-Word FIFO and Interface Logic 72 dB SNR at 10 kHz Input Frequency Interfaces to High Speed DSP Processors, e.g., ADSP-2100, TMS32010, TMS32020 41 ns max 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 AD7878 is a fast, complete, 12-bit A/D converter with a versatile DSP interface consisting of an 8-word, first-in, first-out (FIFO) memory and associated control logic. The FIFO memory allows up to eight samples to be digitized before the microprocessor is required to service the A/D converter. The eight words can then be read out of the FIFO at maximum microprocessor speed. A fast data access time of 41 ns allows direct interfacing to DSP processors and high speed 16-bit microprocessors. An on-chip status/control register allows the user to program the effective length of the FIFO and contains the FIFO out of range, FIFO empty and FIFO word count information. The analog input of the AD7878 has a bipolar range of ± 3 V. The AD7878 can convert full power signals up to 50 kHz and is fully specified for dynamic parameters such as signal-to-noise ratio and harmonic distortion. The AD7878 is fabricated in L...