ADC912A

a FEATURES Low Cost Low Transition Noise between Code 12-Bit Accurate ؎1/2 LSB Nonlinearity Error over Temperature No Missing Codes at All Temperatures 10 ␮ s Conversion Time Internal or External Clock 8- or 16-Bit Data Bus Compatible Improved ESD Resistant Design Latchup Resistant Epi-CMOS Processing Low 95 mW Power Consumption Space-Saving 24-Lead 0.3" DIP, or 24-Lead SOIC APPLICATIONS Data Acquisition Systems DSP System Front End Process Control Systems Portable Instrumentation GENERAL DESCRIPTION CMOS Microprocessor-Compatible 12-Bit A/D Converter ADC912A FUNCTIONAL BLOCK DIAGRAM AGND VREFIN AIN 5k⍀ 12-BIT DAC VDD VSS ADC912A SUCCESSIVE APPROXIMATION REGISTER 12-BIT LATCH 4 8 CONTROL LOGIC BUSY CS RD HBEN MULTIPLEXER 8 THREE-STATE OUTPUT DRIVERS THREE-STATE OUTPUT DRIVERS CLOCK OSCILLATOR CLK OUT CLK IN D11 D8 D7 D4 DGND D3/11 D0/8 The ADC912A is a monolithic 12-bit accurate CMOS A/D converter. It contains a complete successive-approximation A/D converter built with a high-accuracy D/A converter, a precision bipolar transistor high-speed comparator, and successiveapproximation logic including three-state bus interface for logic compatibility. The accuracy of the ADC912A results from the addition of precision bipolar transistors to Analog Devices’ advanced-oxide isolated silicon-gate CMOS process. Particular attention was paid to the reduction of transition noise between adjacent codes achieving a 1/6 LSB uncertainty. The low noise design produces the same digita...