Re: [SI-LIST] : Output shorted to Ground!

D. C. Sessions (dc.sessions@tempe.vlsi.com)
Wed, 07 Jan 1998 13:58:24 -0700

Gopala Krishna M.R. wrote:
>
> Hi,
>
> Accidentally outputs of (18 bit register Chip) a register were shorted
> to Ground line for more than 2 minutes. The outputs were toggling at
> 16MHz rate.
>
> But when it was realised that the ouputs were shorted to
> Ground, the system was immediately powered off. Checked whether those
> registers have gone bad or not, but all of of them were working fine!
> Searched in the data books for the information, but could not find a
> suitable one. Can any one explain about it?

CMOS transistors have a negative temperature coefficient of
transconductance and Idsat. You *might* have gotten the IC
hot enough to damage or age something, or you might have
pushed the electromigration limits of the power wiring (but
two minutes isn't much for that). Chances are, though,
that only *very* sensitive parametric testing would disclose
any changes, esp. if you were operating in a cool environment.

-- 
D. C. Sessions
dc.sessions@tempe.vlsi.com