An optical receiver achieving 2.5 Gbit/s bit-rate was realized in a 0.25 /spl mu/m CMOS process. The preamplifier has a bandwidth of 1.5 GHz, and an input referred current noise of 9 pA//spl radic/Hz. It is followed by three post amplification stages with automatic offset control. The receiver is fully packaged and consumes only 36 mA (65 mA with the complete test circuits and output buffers) from a low power supply voltage of 2 V.