Re: [SI-LIST] : How to identify SSO

Andrew Ingraham (ingraham@wrksys.ENET.dec.com)
Thu, 8 Jan 98 05:54:36 EST

> One thing that has always concerned me with SSO is the affect of the VCC
> drop on non-switching signals. Theses signal would have noise on them
> that would mimic the VCC noise on chip (since their outputs are
> effectively shorted to VCC).

Indeed. Even worse, since noise margin is usually smaller in the
low state than the high state, is the GND bounce killing your noise
margin on those outputs that are supposed to be LOW.

You may need to assume that ALL outputs go indeterminate on every
clock cycle, whether they switch or not. Clock or clock-like
outputs need special treatment to keep them usable as clocks.

Regards,
Andy