With shrinking feature size and growing integration density in the Deep Sub-
Micron (DSM) technologies, the global buses are fast becoming the "weakest-links"
in VLSI design. They have large delays and are error-prone. Especially, in system-onchip
(SoC) designs, where parallel interconnects run over large distances, they pose
difficult research and design problems. This work presents an approach for evaluating
the data carrying capacity of such wires. The method treats the delay and reliability
in interconnects from an information theoretic perspective. The results point to an
optimal frequency of operation for a given bus dimension for maximum data transfer
rate. Moreover, this optimal frequency is higher than that achieved by present day
designs which accommodate the worst case delays.
This work also proposes several novel ways to approach this optimal data transfer
rate in practical designs.From the analysis of signal propagation delay in long wires,
it is seen that the signal delay distribution has a long tail, meaning that most signals
arrive at the output much faster than the worst case delay. Using communication theory,
these "good" signals arriving early can be used to predict/correct the "few"
signals that arrive late. In addition to this correction based on prediction, the approaches
use coding techniques to eliminate high delay cases to generate a higher transmission rate.
The work also extends communication theoretic approaches to other areas of
VLSI design. Parity groups are generated based on low output delay correlation to
add redundancy in combinatorial circuits. This redundancy is used to increase the
frequency of operation and/or reduce the energy consumption while improving the
overall reliability of the circuit.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/5929 |
| Date | 17 September 2007 |
| Creators | Singhal, Rohit |
| Contributors | Choi, Gwan S, Mahapatra, Rabi N. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 1742943 bytes, electronic, application/pdf, born digital |
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