Design Techniques for On-Chip Global Signaling Over Lossy Transmission Lines.

This thesis describes techniques for global high-speed signaling over long (~10mm) lossy chip-serial transmission lines. With the increase in clock frequencies to multi-GHz rates, it has become impossible to move data across a die in a single clock cycle using conventional parallel bus-based communication. There are also reliability problems due to timing errors, skew, and jitter in fully synchronous systems. Noise, coupling, and inductive effects become significant for both intermediate length and global routing. A new on-chip lossy transmission line technique is developed and new driver and receiver circuitry for on-chip serial links are described. High-speed long-range serial signaling is best done over transmission lines. However, because of the relatively high sheet resistance of metal interconnect layers, on-chip transmission lines tend to be lossy. Matched termination with resistors and the proper selection of the characteristic impedance of the transmission line structure can effectively suppress ISI. Fast digital CMOS technology allows pulsed mode data drivers to operate at multi-GHz rates. A phase-tuned receiver samples and de-serializes the received signal. Since the sampling instant is tuned to match the received signal eye, there is no requirement to match the clock and signal routing or clock and signal delays. A complete self-testing on-chip transceiver communicating over a 5.8mm on-chip transmission line is implemented in 0.13um CMOS and tested. The measured BER at 9Gbps is less than 10^-10. Interleaving is usually necessary in high serial data rate serializer and de-serializer circuits. Multi-stage LC oscillators can be used to generate low phase noise multi-phases clocks required for interleaving. Conventional coupling between oscillators introduces out of phase currents, and this out of phase current causes a lower effective quality factor for each oscillator stage. However, capacitive coupling, a new technique, introduces in phase coupling between stages. Increased coupling with a ring of capacitors decreases phase spacing error dramatically and, in addition, the phase noise of multi-stages is also decreased thanks to in-phase coupling.Ph.D.Electrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/58491/1/parkjy_1.pd