Design of a 25Gbps CTLE based on adjustable mid-frequency equalization and wide-bandwidth binaural negative capacitor

Abstract

In order to improve the signal quality in the RX (receiver), a 25Gbps continuous-time linear equalizer (CTLE) based on 55nm process design is proposed. The proposed circuit adds a pair of zero and pole that can modulate mid-frequency equalization, and it includes a new binaural structure negative capacitance circuit that can achieve a wider bandwidth compared to the traditional CTLE. The simulation results show that, when the 25 Gb/s NRZ signal is transmitted through the 35 cm FR4 PCB trace, the proposed circuit can compensate for a channel loss of 13dB at the Nyquist frequency, the eye diagram opens up significantly with 0.95UI eye width and 1.1V voltage swing.