In one embodiment, a method for selecting transistor threshold voltages on
an integrated circuit may include assigning a first threshold voltage to
selected groups of transistors such as cell instances, for example, and
determining which of the selected groups of transistors to assign a
second threshold voltage, that is lower than the first threshold voltage,
by iteratively performing a cost/benefit analysis. The method may further
include determining which of the selected groups of transistors having a
third threshold voltage to assign the first threshold voltage by
iteratively performing a cost/benefit analysis. The cost/benefit analysis
may include calculating a cost/benefit ratio for each group of the
selected groups of transistors. In addition, the cost/benefit analysis
may include calculating an upcone benefit and a downcone benefit for
groups of transistors coupled to one or more inputs and outputs,
respectively.