Most progress has been seen in the field of analog, mixed
analog–digital, and multilevel analog simulation, where many
commercial applications are already available. Nearing completion
is the standardization of analog and mixed-signal hardware
description languages. Progress has been made in custom analog
circuit and layout synthesis, but only at the research level. Practical
applications may come in the areas of numerical and combinatorial
optimization tasks, linked by various forms of sensitivity analysis
and constraint mapping. The overriding need is for an analog
design—carried out in a systematic and structured way, supported
by methodologies and tools—that fits into the overall mixed-signal
system design flow.