wanted: 91 or 92 ohm resistor networks

Dwight K. Elvey dwight.elvey at amd.com
Thu Feb 17 11:32:45 CST 2005


>From: "Brian Knittel" <brian at quarterbyte.com>
>
>Thanks for the ideas. Sellam suggested in an
>off-list email visiting Excess Solutions, Weird Stuff
>etc. Excess Solutions will be a good place to check --
>it's very well organized. Mike Quinn's probably
>has them, but who would ever be able to find them?
>
>The handmade-network-from-discrete resistors idea is
>good too. This is for a PC board I'm laying out, so
>if I can't get SIP networks I may just waste
>the space and lay the 30-some-odd discrete resistors
>down on the board. Or, hmm, maybe standing them up
>is OK too. We'll see.
>
>Brian
>

Hi Brian
 The standard carbon film 1/4W can stand up on
the same 0.1 inch grid as the pre-made rpacks.
I'd just lay it out for the resistors.
 It may also be that the best value is not 91 ohms.
The original board material may be different and
surely your trace width and spacing will be
different than the original. The desired resistance
may actually be anywhere from about 35 ohms to
100 ohms someplace. Most drivers don't work well
at the lower end of the range that board traces
can go in impedance. If you can, try to keep
the trace impedance in the order of 75 ohms.
Dwight





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