A 65-mW 5-Gb/s/ch current-mode common-base transimpedance amplifier array for optical interconnects

Abstract

A four-channel photoreceiver array with 20-Gb throughput has been realized in a 0.8-mum Si-SiGe heterojunction bipolar transistor technology for parallel optical interconnect applications. Each channel includes a transimpedance amplifier exploiting the current-mode common-base input configuration to achieve efficient isolation of the large input parasitic capacitance. The chip module demonstrates the -3-dB bandwidth of 4.1 GHz for 0.25-pF photodiode capacitance, the midband transimpedance gain of 3.2 kOmega, the, average noise current spectral density of 7.4 pA/rootHz, and -19-dBm optical sensitivity for the bit-error rate of 10(-10). Also, the array obtains less than -20-dB crosstalk between adjacent channels. The chip dissipates 65 mW in total from +/-2.5-V supply.