Reducing clock skew variability via cross links

Increasingly significant variational effects present a great challenge for delivering desired clock skew reliably. Non-tree clock network has been recognized as a promising approach to overcome the variation problem. Existing non-tree clock routing methods are restricted to a few simple or regular structures, and often consume excessive amount of wirelength. In this paper, we suggest to construct a low cost non-tree clock network by inserting cross links in a given clock tree. The effects of the link insertion on clock skew variability are analyzed. Based on the analysis, we propose two link insertion schemes that can quickly convert a clock tree to a non-tree with significantly lower skew variability and very limited wirelength increase. In these schemes, the complicated non-tree delay computation is circumvented. Further, they can be applied to the recently popular non-zero skew routing easily. The effectiveness of the proposed techniques has been validated through SPICE based Monte ...

• Type: Conference
• Year: 2004
• Where: DAC
• Authors: Anand Rajaram, Jiang Hu, Rabi N. Mahapatra
• Keywords: Clock Routing Methods, Clock Skew Variability, DAC 2004, Design Automation, Lower Skew Variability