From: D. C. Sessions ([email protected])
Date: Wed Dec 15 1999 - 15:03:38 PST
Eric Goodill wrote:
> I want to use the typical LVDS termination where you have two 50-ohm resistors in series placed between the two lines of the LVDS diff. pair and also have a cap at the junction of the resistors to ground. I have a jillion LVDS pairs to terminate at a high-pin-count ASIC, and I'm looking to squeeze more terminations per square inch. (There's no hope of putting the terminations inside the ASIC at this point.) I'm hoping some company makes a single three-pin part the has those two resistors and a cap even if not specifically for termination use.
>
> How about any other ideas for even higher density?
Well, a newline every 60-70 mcolumns would help :-)
Seriously, you should be able to skip the cap and just use a 100-ohm resistor.
Especially if you're running both ends of the line on a common ground.
Alternately, use a pullup pack (several 50-ohm resistors to a common pin)
and one cap. The application you're describing sounds like all of the pairs
come over a common path, so they should have pretty well-matched common-mode
potentials.
-- D. C. Sessions [email protected]**** To unsubscribe from si-list: send e-mail to [email protected]. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****
This archive was generated by hypermail 2b29 : Tue Feb 29 2000 - 11:39:07 PST