High speed, low power input/output circuit for a multi-chip module

摘要

An I/O transceiver circuit for use on each integrated circuit of a multi-chip module that controls the threshold voltage of the receiver portion and also controls the output resistance of the transmitter portion. Control of the threshold voltage allows operation of the circuit at low voltage levels and with relative immunity from process and temperature variations. Control of the output resistance allows operation without characteristically terminated I/O lines between multi-chip modules, thereby saving power otherwise wasted in the terminating resistors. Control of the threshold voltage is achieved by means of a reference circuit. Control of the output resistance is achieved by a phase-locked-loop arrangement. Further, the I/O transceiver circuit may also have a state where it clamps noise pulses on its I/O line.