AD7725

16-Bit 900 kSPS ⌺-⌬ ADC with a Programmable Postprocessor AD7725 FEATURES Programmable Filtering: Any Characteristic up to 108 Tap FIR and/or IIR Polynomial Signal Conditioning up to 8th Order Programmable Decimation and Output Word Rate Flexible Programming Modes: Boot from DSP or External EPROM Parallel/Serial Interface Internal Default Filter for Evaluation 14.4 MHz Max Master Clock Frequency 0 V to +4 V (Single-Ended) or ؎2 V (Differential) Input Range Power Supplies: AVDD, DVDD: 5 V ؎ 5% On-Chip 2.5 V Voltage Reference 44-Lead MQFP Package TYPICAL APPLICATIONS Radar Sonar Auxiliary Car Functions Medical Communications FUNCTIONAL BLOCK DIAGRAM AVDD AGND AD7725 2.5V REFERENCE POSTPROCESSOR DEFAULT FILTER (ROM) REF2 REF1 VIN (+) VIN (–) MOD PRESET FILTER DVDD DGND UNI HALF PWR STBY SYNC S/ P XTAL CLOCK XTAL_OFF XTAL CLKIN SMODE1/DB15 SMODE0/DB14 SCR/DB13 CFGEND/DB12 DB11 DB10 FSO/DB9 RD/ WR SOE / CS CFMT/RS DVAL /INT SDI/DB0 CONTROL LOGIC GENERAL DESCRIPTION The AD7725 is a complete 16-bit, ⌺-⌬ analog-to-digital converter with on-chip, user-programmable signal conditioning. The output of the modulator is processed by three cascaded finite impulse response (FIR) filters, followed by a fully user-programmable postprocessor. The postprocessor provides processing power of up to 130 million accumulates (MAC) per second. The user has complete control over the filter response, the filter coefficients, and the decimation ratio. The postprocessor permits the signal con...