Low-Power SiGe BiCMOS Transimpedance Amplifier for 25-GBaud Optical Links

We propose a new circuit for the realization of transimpedance amplifiers (TIAs), targeted at reducing the input-referred noise of the TIA or alternatively increasing the bandwidth, without increasing the power dissipation. An intensive theoretical analysis of the method is given. A prototype chip is fabricated in 0.25-
$\mu\hbox{m}$
SiGe BiCMOS technology. The TIA has a gain of 71
$\hbox{dB}\Omega$
, a bandwidth of 20.5 GHz, and an average input-referred current noise density of 18
$\hbox{pA}/\surd \hbox{Hz}$
. The circuit operates from a 2.5-V supply, and power dissipation is 57 mW.