A Robust Differential 4x28Gb/s Stacked Optical Receiver in 28nm CMOS Realizing Crosstalk Suppression and Power Supply Rejection

A stacked 4×28Gb/s multi-channel optical receivers with good crosstalk and power supply noise suppression is presented in this paper. Each channel is consisted of a transimpedance amplifier (TIA), a two-stage level shifter (LS), a post amplifier (PA) and an output buffer (OB), realizing 66dBΩ transimpedance gain and 21GHz bandwidth. The receiver adopts P-type current-mode-logic (CML) pseudo-differential architecture, making it robust to power supply noise and crosstalk. The fully integrated power supply is comprised of a main LDO and three assist LDOs. The stacked receivers consume 58.9mW from 3.3V supply, in which the power supply regulator dissipates 2.3mW.