Input current leakage correction for multi-channel LVDS front multiplexed repeaters

摘要

A high-speed front-multiplexed multi-channel LVDS-compatible repeater circuit that limits input leakage current levels in the event one or more input voltages of the circuit exceeds the supply voltage. The LVDS repeater includes a multiplexor having a plurality of differential inputs and at least one differential output. The multiplexor includes a plurality of transmission gates to allow any one of the differential inputs to be routed to any differential output. Each transmission gate includes a first PMOS transistor and an NMOS transistor. The multiplexor further includes first Schottky diodes coupled between Vcc and the back-gate nodes of the first PMOS transistors, and second PMOS transistors coupled as shunts between the gate nodes of the first PMOS transistors and the source nodes of the NMOS transistors. The first Schottky diodes block the back-gate diode-to-Vcc leakage current paths and the second PMOS transistors block the leakage current paths from the differential inputs to the first PMOS transistors when the input voltage exceeds Vcc.