A 3\,×\,3.8 Gb/s Four-Wire High Speed I/O Link Based on CDMA-Like Crosstalk Cancellation

Code division multiple access (CDMA) principles have been shown to suppress the signal crosstalk caused by inevitable circuit and transmission-line mismatches in a four-wire chip-to-chip electrical signaling system. This paper describes the CDMA-like crosstalk cancellation technique, and discusses equalization and clocking issues in the four-wire simultaneous differential- and common-mode signaling system based on the technique. The implementation and measurement of a 3 × 3.8 Gb/s, 10-12BER, prototype IC built in a standard 90 nm CMOS technology are also described as a proof of concept.