Flash analog-to-digital converter with latching exclusive or gates

摘要

The number of input latching comparators in a flash analog-to-digital converter is significantly reduced by merging the input latching function into exclusive OR gates used in the converter's decoding section. A latching exclusive OR gate used for this purpose employs resonant tunneling diodes as the latching devices, with hysteresis and impedance elements connected to ensure that the gate latches in a logic state that corresponds to the input analog signal. The latching logic gates operate in a current mode, enabling updated logic states to be latched in response to a periodic clock signal.