The automated improvement of analogue integrated circuits

Concerns techniques whereby a computer automatically suggests new values for certain designable parameters with a view to improving circuit performance. There are many reasons why one needs such techniques for the automated improvement of integrated circuits. In the most familiar case the designer may have done the best he or she can, and produced a circuit which meets specifications, but wishes to discover whether any improvement is possible via the adjustment of parameter values. Or a circuit may have been passed to a layout module and the extracted parasitics added to the circuit model to produce what is, in effect, a new circuit which must be readjusted to satisfy the specifications. Alternately, within one of the emerging analogue synthesis systems, some simple design rules may have been used to automatically generate a `first cut´ circuit design which then needs to be adjusted to bring it closer to the desired performance. Further adjustment may also be needed, in a procedure called tolerance design, to compensate for the reduction in manufacturing yield which might occur due to the inevitable tolerances on component values