An 8 bit, 100 ms/s flash ADC

An 8-bit flash ADC capable of operation at a sampling rate higher than 100 MHz with only 1.2 W of power dissipation is described. This good performance is realized using: (1) a small transistor utilizing oxide isolation and a thick field oxide process with small parasitic capacitances; (2) an optimized design for speed, accuracy, and power; and (3) a simple comparator design with small component count. Analog input capacitance of 35 pF and full-scale bandwidth of higher than 40 MHz were obtained. An error under the beat frequency test was eliminated by decoupling the master and the slave latches of the comparator.