A single-to-differential broadband transimpedance amplifier for 12.5 Gb/s optical links.

A broadband transimpedance amplifier (TIA) is designed and analyzed based on Regulated Cascode (RGC) configuration with L-matching network and cascode amplifier. A novel single-to-differential amplifier is also designed to simplify the following limiting amplifier (LA) design and increase the immunity of common-mode noise. The TIA is implemented in UMC 0.18 mu m standard CMOS process. The measured transimpedance gain is 57 dBO with a -3 dB bandwidth of 8.1 GHz. The average equivalent input noise current spectral density is 29 pA/v Hz. The chip consumes 68mW DC power under 1.8V and occupies the area of 0.9mm(2).