Issue No. 01 - January/February (1997 vol. 17)
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/40.566199
To operate a serial channel over copper wires at 4 Gb/s, we incorporate an 4-GHz FIR equalizing filter into a differential transmitter. The equalizer cancels the frequency-dependent attenuation caused by the skin-effect resistance of copper wire, giving a frequency response that is flat to within 5% over the band from 200 MHz to 2 GHz even over wires with 6 dB of high-frequency attenuation. All but the last stage of the transmitter operates at 400 MHz. The transmitter output stage uses a stable, 10-phase, 400-MHz clock to sequence an array of drivers that implement the FIR filter. We introduce the concept of digital-signal equalization, describe the system design, and circuit design of our equalizing transmitter, and present simulation results from a 4-Gb/s 0.5-mm CMOS transmitter.
Interconnects, transmission equalization, digital-signal equalization, circuit design
J. Poulton and W. J. Dally, "Transmitter Equalization for 4-GBPS Signaling," in IEEE Micro, vol. 17, no. , pp. 48-56, 1997.