A 90-Gb/s 2:1 Multiplexer with 1-Tap FFE in SiGe Technology

A 2:1 multiplexer with built-in 1-tap FFE is designed in a SiGe technology with f_T of 210 GHz and f_MAX of 260 GHz. The FFE is implemented with a delay and a secondary selector. The circuit is able to equalize cable loss of up to 12 dB at 90 Gb/s and 14 dB at 80 Gb/s, while operating from a -3.3 V supply. Error-free operation of the MUX was verified with 2³¹-1 PRBS up to 40 Gb/s, which is the limit of the available error detector.