A 48-Port FCC-Compliant 10GBASE-T Transmitter With Mixed-Mode Adaptive Echo Canceller

High density 48-port network switches demand very power-efficient, small form-factor physical layer transceivers which comply with the transmit PSD and return loss requirements, on the one hand, and meet the FCC Class-A specifications on the other hand, while achieving better than 10E-12 BER. The presented 10GBASE-T transmitter and hybrid utilize a current-mirroring amplifier with output rise-time control and high CMRR to perform a first-order linear and nonlinear echo cancellation while enabling the design of 48-port FCC compliant network switches. Experimental results over the 400-MHz bandwidth exhibit a worst case transmitter linearity of >;57 dBc as well as worst case post-hybrid fundamental and SFDR power of -18 and -70 dBc, respectively, across the 400-MHz frequency range of interest. The echo fundamental component is further attenuated to <; -60 dB in the analog domain by an adaptive mixed-mode echo canceller. Implemented in a 40-nm CMOS technology, the transmitter plus hybrid consumes 200 mW power and occupies 0.5 mm².