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Circuit and signaling techniques for on -chip interconnects

Atul Maheshwari, University of Massachusetts Amherst


As VLSI progresses into Very Deep Submicron (VDSM) realms, global interconnects play an increasingly important role in the overall performance and power consumption of high-performance chips. This thesis proposes circuit and signaling solutions to the on-chip interconnect design problem. Current-sensing and phase coded signaling are proposed as potential techniques to transmit logic in current and time respectively. A test-chip verifying these techniques has been fabricated in a TSMC 0.18μ technology through MOSIS. Using a novel receiver circuit for differential current-sensing, a performance benefit of 20% was obtained over the delay-optimal repeater insertion technique. The proposed single ended current-sensing provides more delay benefits (45% on average) and like repeaters uses one wire to transmit a data bit. The static power dissipation in current-sensing is mitigated by using transition encoded current-sensing and current-pulse signaling. These techniques are faster and lower power than repeater insertion. A hybrid circuit technique that exploits the advantages of both current-sensing and repeater insertion is proposed. Phase coding is presented as a multi-bit signaling technique which encodes multiple bits on a single wire in terms of phase information. Transmitting multiple bits saves power and increases bandwidth. DLL based closed loop encoding and decoding schemes provide process-variation immune operation.

Subject Area

Electrical engineering

Recommended Citation

Maheshwari, Atul, "Circuit and signaling techniques for on -chip interconnects" (2004). Doctoral Dissertations Available from Proquest. AAI3152726.