A wideband differential transimpedance amplifier of an optical receiver is realized in a 0.18/spl mu/m standard CMOS technology for the applications of Gigabit Ethernet data communication. The amplifier incorporates the regulated cascode (RGC) configuration to achieve strong immunity to large input parasitic capacitance and also exploits shunt inductive peaking technique to extend the bandwidth. Consequently, the RGC TIA has negligible effect on bandwidth from the large variation of photodiode capacitance. HSPICE simulations demonstrate the transimpedance gain of 60dB/spl Omega/, the -3dB bandwidth of 11GHz for 0.25pF photodiode capacitance, the average noise current spectral density of 18 pA//spl radic/Hz which corresponds to -14.4dBm optical sensitivity for 0.5A/W responsivity and 9dB extinction ration, and the DC power dissipation of 22mW from a single 1.8V supply.