A 2^nd-order CTLE in 130nm SiGe BiCMOS for a 50GBaud PAM4 Optical Driver

In this paper, we presented a low frequency equalizing continuous time linear equalizer (LFEQ-CTLE). It can compensate not only the low-frequency channel loss but also the high-frequency channel loss. The LFEQ-CTLE adopts the degeneration R-C and negative feedback loop to generate the high frequency zero/pole and low frequency zero/pole. Based on Global Foundry $130nm$ SiGe BiCMOS process to achieve the overall design, the proposed CTLE compensates for the 17dB channel loss at Nyquist frequency for 50GBaud PAM4 data rates.