A 20-Gb/s transformer-based current-mode optical receiver in 0.13-µm CMOS

20-Gb/s current-mode optical receiver is realized in a 0.13-µm CMOS process, which consists of a common-gate transimpedance amplifier (TIA) with on-chip transformers, a six-stage postamplifier (PA) with an offset cancellation network, and an output buffer. The transformer-based inductive peaking technique is exploited in the TIA to isolate the parasitic capacitances at high-impedance nodes and, hence, to enlarge the bandwidth. The PA incorporates source degeneration and interleaving active feedback techniques to achieve wide bandwidth and flat frequency response so as not to degrade the operation speed of the whole optical receiver. Measured results demonstrate 60-dBΩ transimpedance gain, 12.6-GHz bandwidth even with 0.4-pF large input parasitic capacitance, -13-dBm sensitivity for a 10-12 bit error rate, and 38.3-mW power consumption from a single 1.2-V supply.