Xindong Xiao

A fully differential transimpedance amplifier with integrated differential photodetector in standard CMOS process for optical communications and interconnects

A fully differential transimpedance amplifier (TIA) with integrated differential photodetector in standard CMOS technologies has been realized for optical receivers in optical communications and optical interconnects. And a novel, fully differential photodetector aiming to convert the incident light into a pair of fully differential photo-generated currents and ensure the differential symmetry on circuit configuration and model has also been proposed for the differential TIA to achieve the fully differential characteristic. Theoretical analysis and simulation results both indicate that the fully differential TIA reaches a higher bandwidth than a conventional one and at the same time a doubled sensitivity. Based on this new TIA, a monolithic, fully differential optoelectronic integrated receiver was designed and implemented in a Chartered 3.3 V, 0.35 μm standard CMOS process. It demonstrates 98.75 dBΩ transimpedance gain, and 0.334 μA equivalent input integrated referred noise current from 1 Hz up to −3 dB frequency. The power dissipation from a single 3.3 V supply is 100 mW for the TIA-LIA (limiting amplifier)-combination plus 138 mW for the 50 ω output buffer. At 850 nm wavelength, the optical receiver achieves a 1.1 GHz 3 dB bandwidth, and can handle bitrates up to 1.6 Gbit/s for −12.2 dBm peak-peak optical power and 231−1 PRBS (pseudorandom bit sequency) input signal.

A 13GHz 38mW differential front-end amplifer based on 0.18um SiGe BiCMOS For 15Gb/s optical receiver

A high bandwidth, lo w power consumption, low noise front-end amplifier is designed based on standard 0. 18um SiGe BiCMOS process. This front-end amplifier consists of a high performance differential RGC TIA, a 3 stage post amplifier and a buffer. The single stage of post amplifier is Cherry-Hooper amplifier. The entire circuit is simulated by a commercial software Cadence. The bandwidth and the differential transimpedence of the front-end amplifier are 13.22GHz and 87.3dBΩ with the input-referred r ms noise current 1.71μA and the power consumption 38.6mW.