High linearity transimpedance amplifier in 0.18-μm CMOS technology for 20-Gb/s PAM-4 receivers

In this paper, a high-linearity transimpedance amplifier (TIA) with automatic gain control (AGC) was designed in 0.18-μm CMOS Technology. For 700-μA input current amplitude, the total harmonic distortion (THD) of the TIA can be below 5%. The bandwidth of the TIA is 7.29-GHz, and its input referred current density is about 23.6-pA/√Hz. The TIA can be used in 20-Gb/s four-level pulse amplitude modulation (PAM-4) optical receivers. The power dissipation of the chip is 37.8-mW, and the chip area is 0.307-mm ² .