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In DSM technologies, the switching capacitance of a wire depends
on its neighbors' switching activity, which determines how the
coupling capacitances between wires are charged and
discharged [43]. Several interconnect energy models
have been proposed to take the coupling effect into
consideration [47,48,49,50].
Given the wire capacitive parameters, these models generate the
unit-length switched capacitance or energy based on switching
patterns on a wire and its neighbors. We use the table look-up
method proposed in [48], which is shown in
Fig. 6 as the local power model. Other models, such
as the one proposed in [49], can be readily
incorporated into the synthesis flow used in our work. According
to [48] we only consider the coupling from
the direct neighbors, we need to find out the unit-length switched
capacitance of a wire when itself and its two neighbors undergo
different switching patterns, which we called *three-line
switching patterns* as shown in Fig. 6. There are
10 different patterns in terms of power
consumption [48]. Using this method, PSPICE
and capacitance data from [43], we estimated the
unit-length switched capacitance of the central lines for
different three-line switching patterns. These data are stored in
a table, called *pattern-power table*, for later use. If
multiple metal layers are used, wires on different layers will
have different capacitive parameters. For each layer, we need to
generate a different pattern-power table. Together with the length
of a wire, its layer assignment and three-line switching patterns,
these tables can be used to estimate power consumed by the entire
wire.

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** Up:** Data transfer wires
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Lin Zhong
2003-10-11