A 56-Gb/s 10.46-$\text{pA}{/}$ ${\!}\sqrt{\text{Hz}}$ Input Noise Linear TIA With 31-dB Dynamic Range in 22-nm CMOS

This brief proposes a novel optical receiver featuring wide bandwidth and low noise, with a flat frequency response across a large dynamic range without bandwidth peaking. A wide dynamic range transimpedance input stage (WDR-TIS) is proposed as the input-stage amplifier of proposed transimpedance amplifier (TIA). This structure maintains a relatively constant bandwidth during high transimpedance gain dynamic range while delivering adequate noise performance. A three-stage variable gain amplifier (VGA) provides a dynamic range up to 22 dB with excellent linearity, and can accommodate an input current up to 2.8 mApp. Measurement results show that the proposed optical receiver provides an electrical transimpedance gain (ZT) of 40.9 to 72.6 dBΩ with bandwidth beyond 18.8 GHz and input-referred noise density (IRND) current of 10.46 pA/ √Hz. The total harmonic distortion (THD) is less than 4% for the output amplitude up to 450 mVppd. The core of proposed optical receiver achieves a power dissipation of 85 mA from 1.5 V supply and occupies an area of 0.53×0.36 mm2in 22 nm standard CMOS process.