RE: [SI-LIST] : BusHolders: still necessary if SI mananged proper ly ?

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From: Ingraham, Andrew (Andrew.Ingraham@compaq.com)
Date: Tue Nov 09 1999 - 08:50:31 PST


>I have a question about Bus holders in regards to their necessity,
>If I make an effort to control/manage the signal integrity on a controller
>platform,
>Would there be a strong need to still use Bus Holders for the TriState
buses ?

My first reaction is that Bus Holders help solve a DC problem and have
little if anything to do with signal integrity.

If a bus can be left in a hi-Z state for a long time, so that it might drift
to an undefined voltage level, that's a place where a Bus-Hold device may be
useful. Even if the SI is clean.

If you handled an SI problem by parallel terminating the bus with a stiff
pull-up or pull-down, thus preventing it from so drifting, then Bus Holders
aren't needed. Other than that, I see little relationship between one and
the other.

Regards,
Andy

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