Special Topics in Computer Science
Department of Computer Science and Information Engineering
National Chung Cheng University
April 7, 2003
Bus Delay Reduction for Deep Submicron Technology
While the technology parameters get into deep sub-micron, interconnection wire
delay influences a chip performance greater than gate delay. Especially, bus
is consumed by interconnect delay. Many techniques for interconnect delay
reduction based on buffer insertion have been presented. In general, the
propagation delay signal ran on interconnections is considered on RC model and
exhibits tolerance error as compared to SPICE. The inductance effect in RC
model is almost neglected since the work frequency is not high enough.
However, the frequency of current chips has worked over 1GHz, the inductance
existed in interconnection cannot be neglected again and it is becoming more
important with faster on-chip rise times and longer wire length. Thus, the
calculation of propagation delay has transferred to the consideration of RLC
model for high performance chip. Fewer papers investigated on RLC mode have
contributed to the interconnection delay estimation.
We propose an algorithm to reduce the propagation delay in a multi-source
multi-sink bus with considering RLC model for the bus. The algorithm based on
buffer or repeater insertion and sizing is employed to minimize the maximum
delay in a bus. Experimentally, the results for some test examples are the
delay reduction of 48%, 87.42%, and 62.63% in average for 0.18 .m, 0.35.m and
0.5.m technologies, respectively.