A Current Reuse Regulated Cascode CMOS Transimpedance Amplifier With 11-GHz Bandwidth

A transimpedance amplifier (TIA) for use in high-bandwidth balanced photoreceivers is designed and demonstrated. The circuit, based on the regulated cascode (RGC) TIA, utilizes the current reuse strategy to provide performance increase and additional benefits over the traditional RGC TIA. Implemented in a 65-nm general-purpose CMOS process, the current reuse RGC TIA achieves a transimpedance of 62 dBQ across a -3-dB bandwidth of 11 GHz while consuming 10 mW of dc power, with a unity-gain differential output buffer for driving 50-Ω loads consuming 56 mW. High sensitivity is achieved due to a low equivalent input noise of 30 pA/√Hz. The total active area of the TIA, including an active balun and unity gain output driver, is 0.08 mm
²
, and 0.25 mm
²
with pads.