AD7720

a FEATURES 12.5 MHz Master Clock Frequency 0 V to +2.5 V or ؎ 1.25 V Input Range Single Bit Output Stream 90 dB Dynamic Range Power Supplies: AVDD, DVDD: +5 V ؎ 5% On-Chip 2.5 V Voltage Reference 28-Lead TSSOP CMOS Sigma-Delta Modulator AD7720 FUNCTIONAL BLOCK DIAGRAM AVDD AGND DVDD DGND REF1 AD7720 2.5V REFERENCE REF2 VIN(+) VIN(–) SIGMA-DELTA MODULATOR DATA SCLK MZERO GC CLOCK CIRCUITRY XTAL1/MCLK XTAL2 BIP CONTROL LOGIC DVAL RESETO RESET STBY GENERAL DESCRIPTION This device is a 7th order sigma-delta modulator that converts the analog input signal into a high speed 1-bit data stream. The part operates from a +5 V supply and accepts a differential input range of 0 V to +2.5 V or ± 1.25 V centered about a commonmode bias. The analog input is continuously sampled by the analog modulator, eliminating the need for external sample and hold circuitry. The input information is contained in the output stream as a density of ones. The original information can be reconstructed with an appropriate digital filter. The part provides an accurate on-chip 2.5 V reference. A reference input/output function is provided to allow either the internal reference or an external system reference to be used as the reference source for the part. The device is offered in a 28-lead TSSOP package and designed to operate from –40°C to +85°C. REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for ...