A 24Gb/s Switched-Capacitor Pre-Emphasis for PAM-3 Transmitters with Transition-Level Adaptation

In this study, a switched-capacitor peaking (SCP) feed-forward equalizer (FFE) is proposed to compensate for attenuation and distortion caused by channel loss in high-speed memory interfaces. The proposed SCP achieves both signal integrity enhancement and signal bandwidth preservation by implementing pre-emphasis while minimizing I/O capacitance (CIO). Furthermore, by pre-distorting according to the emphasis coefficient, the overhead of the output driver is minimized. The proposed SCP transmitter, implemented in a 28-nm CMOS process, compensates for −9.2 dB of channel loss at 8 GHz, achieving an energy efficiency of 0.129 pJ/b/dB with vertical and horizontal eye margins of 61 mV and 0.65 UI, respectively.