This paper presents a routing methodology and a routing algorithm used in designing Gb/s LSIs with deep-submicron technology. A routing method for controlling wire width and spacing is adopted for net groups classified according to wire length and maximum-allowable-delay constraints. A high-performance router using this method has been developed and can handle variable wire widths, variable spacing, wire shape control, and low-delay routing. For multi-terminal net routing, a modification of variable-cost maze routing (GVMR) is effective for reducing wire capacitance (net length) and decreasing net delay. The methodology described here has been used to design an ATM-switch LSI using 0. 25-µm CMOS/SIMOX technology. The LSI has a throughput of 40 Gb/s (2. 5 Gbps/pin) and an internal clock frequency of 312 MHz.

A computer-aided low-power design methodology for very high-speed Si bipolar standard cell LSI is described. In order to obtain Gbit/s-speed operation, it features a pair of differential clock channels inside cells and a highly accurate static timing analysis for back annotation. A newly developed CAD-based power optimization scheme minimizes cell currents while maintaining circuit speed. A 5.6 k gate SDH signal-processing LSI operating at 1.6 Gbit/s with only 3.9 W power consumption demonstrates the effectiveness of this design technology.

A timing-driven global routing algorithm is proposed that directly models the path-based timing constraints. By keeping track of the critical path delay and channel densities, and using novel heuristic criteria, it can select routing paths that minimize area as well as satisfy the timing constraints. Using bipolar-specific features, this router can be used to design LSI chips that handle signals with speeds greater that a gigabit per second. Experimental results shows an average delay improvement of 17.6%.

The switch LSI described here takes advantage of the special characteristics of fully-depleted CMOS/SIMOX devicesthat is, source/drain capacitances and threshold voltages that are lower than those of conventional bulk CMOS devicesto boost the I/O bit rate. The double-edge triggered MUX/DEMUX which uses a frame synchronization logic, and the active-pull-up I/O provide a 144-pin, 2. 5-Gbps/pin interface on the chip. The 220-kgate rerouting banyan switching network with 110-kbit RAM operates at an internal clock frequency of 312 MHz. The CMOS/SIMOX LSI consumes 8. 4 W when operating with a 2-V power supply, and has four times the throughput of conventional one-chip ATM switch LSIs.