A Hybrid SST-CML Full Duplex Simultaneous Bi-Directional Signaling Link

This paper presents a full-duplex simultaneous bidirectional (FD-SBD) signaling transceiver designed to overcome the switching supply noise (SSN). The signal-to-noise ratio (SNR) is impacted mainly by transmitter echo signal, inter-symbol interference (ISI), SSN, etc. This paper primarily focuses on comparing the impact of SSN on the transceiver. In general, the voltage mode (VM) transmitter injects more SSN compared to the current mode (CM) transmitter. To address this, the proposed architecture combines voltage mode source series terminated (VM-SST) and current mode logic (CML) transmitters to improve SNR by mitigating the effect of SSN. In addition, this paper proposed a passive R-Gm hybrid for linear and energy-efficient subtraction of the transmitted signal and extracting the received signal. Implemented in TSMC-65 nm CMOS technology for a link with 3 dB insertion loss at 5 GHz Nyquist frequency, the simulated results of the proposed architecture improve the eyeopening by 30% at 10+10 Gb/s SBD data rate.