Circuit techniques for achieving high speed-high resolution A/D conversion

A 12 bit, 25 μs, analog-to-digital converter has been successfully integrated on two process-compatible junction-isolated chips. One chip contains a 200 ns digital-to-analog converter with reference, while the other contains the comparator, an I/SUP 2/L successive-approximation register, multiplexed three-state T/SUP 2/L output buffers, and a controller designed to interface directly to several common microprocessors. The authors describe several innovations which allow this degree of integration at the 12 bit accuracy level.