Wideband SiGe BiCMOS transimpedance amplifier for 20 Gb/s optical links

A novel bandwidth enhancement technique based on a modified regulated cascode (RGC) transimpedance amplifier (TIA) is proposed and realized. The post stage of the TIA adopts capacitive degeneration and pi-type peaking network, maintaining the wideband and low group delay characteristics without increasing power dissipation. The TIA is implemented in a 0.18 mu m SiGe BiCMOS technology and tested with an on-chip 300 fF capacitor to emulate a photodiode. The measured transimpedance gain is 61 dB Omega with a -3 dB bandwidth of 15 GHz. The chip consumes 32 mW power from a single 3.3 V supply and occupies the area of only 0.3 mm(2).