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 mA_pp. Measurement results show that the proposed optical receiver provides an electrical transimpedance gain (Z_T) 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 mV_ppd. 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 mm₂ in 22 nm standard CMOS process.