Designing circuits that work in the real world is challenging. It is not enough just to design the circuit to meet a
specification target. It is also important to accurately predict the behavior of the circuits under a range of
expected conditions, including the realistic variations of the components. Once this behavior is well understood,
the designer can effectively select circuits and components to work with the expected manufacturing tolerances.
Circuits that work even as circuit parameters vary are less expensive to build, test, and support.
This article describes the use of tolerances to generate yield analyses-predictions of how many circuits built with
varying component values will meet spec. To do a useful yield analysis you must have:
l A good model of the circuit including important components, strays, etc.
l A good model of expected component variations
l A definition or specification of pass/fail