0.18-μm CMOS 10-Gb/s multiplexer/demultiplexer ICs using current mode logic with tolerance to threshold voltage fluctuation

A feedback MOS current mode logic (MCML) is proposed for the high-speed operation of CMOS transistors. This logic is more tolerant to the threshold voltage fluctuation than the conventional MCML and is suitable for gigahertz operation of deep-submicron CMOS transistors. Using this logic, 8:1 multiplexer (MUX) and 1:8 demultiplexer (DEMUX) ICs for optical-fiber-link systems have been fabricated with 0.18- mu m CMOS transistors. The ICs are faster than conventional CMOS MUX and DEMUX ICs and their power consumption is less than 1/4 of that of the conventional 10-Gb/s MUX and DEMUX ICs made using Si bipolar or GaAs transistors.