A 5 Gbps low noise receiver in 0.13µm CMOS for wireless optical communications

A wideband, high gain, and low noise optical receiver targeting imaging architectures for optical wireless communications is presented. For line of sight tracking in optical wireless communications, a switching matrix is employed between the pixel/photodetctor array and the transimpedance amplifier. The optical receiver consists of a low noise wideband TIA, where noise and stability are optimized in the presence of the switch, using a series inductor at the input. The TIA is followed by a limiter with offset cancellation and 50 Ω output buffer capable of 900 mv p-p differential output swing over the 50 Ω resistance of measurement equipment. The receiver implemented in IBM 130nm CMOS technology achieves a bit error rate of 10^-12 at 5 Gbps corresponding to 2.8 μA current at the input, in presence of 1 pF input capacitance representing the photodiode. The total power consumption including the on chip 50 Ω differential output buffer is 68 mW from 1.5V DC supply, while the die area including bonding pads and output buffer is 1106 × 895 μm².