A low power 12Gb/s single-stage 1 ： 4 demultiplexer （DEMUX） applied in SONET OC-192 is realized in TSMC＇s mix-signal 0. 25μm CMOS. All of the circuits are in source coupled FET logic （SCFL） to achieve as high a speed as possible and suppress common mode distortions. This DEMUX is featured for achieving singlestage demultiplexing by using a quarter-rate IQ clock. This method not only reduces the components of the DEMUX but also lowers its power dissipation. The fabricated DEMUX operates error free at 12Gb/s by 231 - 1 pseudorandom bit sequences in on-wafer testing. The chip size is 0. 9mm × 0.9mm and the power dissipation is only 210mW with a single 2.5V supply.
A 10 Gbit/s (STM-64, OC-192) 1:4 demultiplexer (DEMUX) with 4-phase clock wasachieved in TSMC's standard 0.25 μm complementary metal-oxide-semiconductor (CMOS) technique. Allof the circuits are in source coupled FET logic (SCFL) to achieve as high as possible speed andsuppress common mode distortions. This DEMUX is featured by constant-delay buffers to generate a4-phase clock and adjust skews of the four channel outputs. The fabricated DEMUX operates error freeat 10 Gbit/s by 2^(31) -1 pseudorandom bit sequences (PRBS) via on-wafer testing. The measured rootmean square (rms) jitter, rising and failing edge of the eye-diagram are 11, 123 and 137 ps,respectively. The chip size is 0.9 mm x 1.2 mm and the power dissipation is 550 mW with a 3. 3 Vsupply.
A 1 ：2 demultiplexer is designed and realized in standard 0. 18μm CMOS technology. A novel high-speed and low-voltage latch is used to realize the core circuit cell. Compared to the traditional source-coupled FET logic structure latch, its power supply voltage is lower and the speed is faster. In addition, the negative feedback is used in the buffer circuit to widen its bandwidth. Measurement results show that the chip can work at the data rate of 20Gb/ s. The supply voltage is 1.8V and the current,including the buffer circuit, is 72mA.
