AD7570

r. ANALOG 8 L.III DEVICES CMOS 10-BitMonolithiAc ID Converter FEATURES 8- and 10-Bit Resolution 20llS Conversion Time Microprocessor Compatibility Very Low Power Dissipation Parallel and Serial Outputs Ratiometric Operation TTL/DTL/CMOS Logic Compatibility CMOS Monolithic Construction O8 BGENERAL DESCRIPTION SThe AD7570 is a monolithic CMOS 10-bit successive approxi- mation AID converter on a 120 by 13 5 mil chip, requiring Oonly an external comparator, reference and passive clocking components. Ratiometric operation is inherent, since an ex- 8 Ltremely accurate multiplying DAC is used in the feedback loop. EThe AD7570 parallel output data lines and Busy line utilize Tthree-state logic to permit bussing with other AID output and Econtrol lines or with other I/O interface circuitry. Two enables FUNCTIONAL DIAGRAM OUT1 OUT2 AIN VREF I I 10 ,..,....--0 DB9 (MSB) DB8 are available: one controls the two MSBs; the second controls 18 DB1 the remaining 8 LSBs. This feature provides the control interface for most microprocessors which can accept only an 8-bit byte. The AD7570 also provides a serial data output line to be used in conjunction with the serial synchronization line. The clock CaMP 8 can be driven externally or, with the addition of a resistor and a capacitor, can run internally as high as 0.6MHz allowing a STRT total conversion time (8 bits) of typically 201ls. An 8-bit short ClK cycle control pin stops the clock after exercising 8 bits, nor- mal...