摘要
Recently, PAM-4 transmitters have been realized at 112Gb/s or even faster to satisfy the continuously growing demands for wireline communications. Although PAM-4 signaling performs two-fold bandwidth efficiency comparing with the NRZ counterpart, the NRZ signal still has the advantage especially in low-loss scenario like ultra-short-reach (USR) interconnection for the optical engine due to its high output swing and better SNR. This talk summarizes the design challenges for the ultra-high-speed wireline transmitters and includes design examples for 100+Gb/s applications with NRZ and PAM-4 signaling.