Apart from reducing the noise, the on-chip bypass
capacitor will even help to regain some of the speed lost due
to the ground bounce. In many applications the ground
bouncc is being reduced by the use of more power and
ground pads which will make the effective inductance less.
However the number of power and ground pads is limited by
the number of T/O pins in different package types. In applications
with restrictions imposed by package type, the use of
an on-chip bypass capacitor in unused space of the chip will
help to reduce the SSO (Simultaneous Switching Output)
noise and improve the speed of the circuit. Interestingly the
reduction in switching noise is found to be saturated at a
certain value of bypass capacitor. Hence, the optimum onchip
bypass capacitor must be determined to use a minimum
of expensive silicon area.