Limiting Amplifiers for Next-Generation Multi-Channel Optical I/O Interfaces in SoCs

We present two fully differential limiting amplifiers with and without inductive peaking, designed and integrated in 0.18mm digital CMOS technology. The key design trade-offs, the importance of inductive coupling between neighboring channels, as well as the design of peaking inductors in a standard process are discussed. The amplifiers, which are intended for multichannel integrated optical receiver arrays, achieve a bandwidth of 4GHz and a gain of 32dB. The silicon area occupied by either amplifier is less than 0.5mm2, while the area of the inductors can be further reduced.