A 11-pA/Hz 5-Gb/s Inductorless Optical Receiver for High-Density Parallel Interface Application

This letter presents a 5-Gb/s inductorless optical receiver (ORX) used for high-density parallel interface application. In order to reduce the active area of single channel and mitigate the magnetic coupling effect, the on-chip inductor is limit-used. By adopting a regulated cascode (RGC) transimpedance amplifier (TIA) and an on-chip low dropout (LDO) regulator, the high-frequency noise and off-chip noise are reduced. A limiting amplifier (LA) utilizing the second-order amplifier cells with active feedback is employed, which can perform peaking characteristics at high frequencies and increase the gain-bandwidth (GBW) product. Implemented in 0.18- $\mu $ m CMOS process, the ORX achieves a measured transimpedance gain of 74 dB $\Omega $ , a −3-dB bandwidth of 3.65 GHz, and an average input-referred current noise density of 11 pA/ $\sqrt {\mathrm {Hz}} $ . The total area occupied by the ORX is 2.686 mm², with a power consumption of 112.9 mW.