The SPICE simulator engendered many new CAD and IC design
efforts and is a cornerstone of current IC designs, but today’s simulators
are frustratingly limited with regard to semiconductor device
models and circuit size complexity. Designers need tools that
can simulate analog or digital circuits separately, but also simulate
truly mixed analog–digital designs. Glued mixed-mode simulators
aim to do just that, the trend, however, being toward a more unified
level of algorithm integration with single-kernel multiple-solver solutions.
There is also the need for higher levels of abstraction to
describe and simulate analog circuits and for standardized analog
hardware description languages (AHDLs). The automatic characterization
of analog circuits, in particular the automatic generation
of analog macromodels or behavioral models from a given design,
continues to be a problem. It could be the biggest obstacle to the
adoption of high-level modeling methodologies and AHDLs in the