Sometimes ground and/or power planes are shared among many devices, and noise from an inadequately decoupled device affects the PDS at other devices. Common causes of this noise are:
•RAM interfaces with inherently high-transient current demands resulting either from temporary periodic contention or high-current drivers
•Large ASICs
When unacceptable amounts of noise are measured locally at these devices, the local PDS and the component decoupling networks should be analyzed.