A 6.5 Gb/s backplane transmitter with 6-tap FIR equalizer and variable tap spacing

Abstract

This paper presents a 6.5 Gb/s transmitter for use in backplane links. This transmitter incorporates a finite impulse response filter with programmable tap spacing in the output driver to compensate for intersymbol interference. Using jitter-minimizing tap weights computed using a behavioral model of the transmitter, it is shown that at 6.5 Gb/s peak-to-peak data-dependent jitter is reduced by over 50% by using a tap spacing of 0.53 unit intervals (UI) instead of the usual 1 UI.