A 10-channel 300-Mb/s/ch replica TIA array with equalizer in 0.18-μm CMOS

This paper presents a 10-channel optical receiver array for Near-InfraRed Spectroscopy (NIRS) Systems. Each channel consists of a replica transimpedance amplifier (TIA) followed by an adjustable linear equalizer (EQ). The replica TIA achieves a high transimpedance gain of 94.6 dBΩ and a bandwidth of 85 MHz. To obtain wider bandwidth, a two-stage fully differential equalizer with tunable capacitor banks is exploited. Post-layout simulations reveal the total transimpedance gain of 100 dBΩ, the -3-dB bandwidth of 200 MHz, and the input noise current spectral density of 2 pA/√Hz for the DC current consumption of 9.4 mW per channel with a single 1.8-V supply. The proposed front-end of NIRS preamplifier is implemented using 0.18-μm CMOS technology.