A 224-Gb/s PAM4 High-Linearity, Energy-Efficiency Differential to Single-Ended Driver in 130-nm SiGe BiCMOS

This paper presents a reconfigurable high-linearity, energy-efficiency 112-GBaud driver with 4-level pulse amplitude modulation (PAM4) scheme in 130-nm BiCMOS. The proposed driver incorporates a continuous-time linear equalizer (CTLE), a diode-connected emitter follower, a high-pass filter (HPF) and a push-pull amplifier.By tuning the emitter degenerated resistor of the CTLE, the driver can achieve variable gain from -0.6dB to 9.3dB. A wide bandwidth is realized by utilizing an emitter degenerated capacitor. The proposed driver can transfer 224-Gb/s PAM4 eye with an energy efficiency of 0.19-pJ/b from 2.5-V supply.