Selectable capacitors are used to modify performance characteristics of
functional circuit elements of an integrated circuit (IC). In one embodiment, the
decoupling capacitors are implemented as additional or alternative mounting pads
on a surface of the IC. At least one selectable capacitor is provided for each
IC circuit element, such as a logic network, whose operational characteristic(s)
is predicted to be and is actually identified as sub-optimal through IC testing,
particularly following a process change, a mask shrink, operation of the IC at
higher clock frequency, or the like. Expensive redesign is avoided by selectively
coupling capacitors into the IC circuit element as needed, under control of selector
logic that is responsive to control signals. Methods of operation, as well as application
of the apparatus to an electronic assembly and an electronic system, are also described.