--- In
Homebrew_PCBs@yahoogroups.com, "D. Daniel McGlothin" <ddm@...> wrote:
>
> > I am looking for the specs for trace width, spacing, and length.
>
> and
>
> > What I need to know is the clearance between pads.
>
>
> Isn't trace/pad spacing at least partly a function of the voltage are
> expected to carry?
No, not for an edge connector. In that case, the pad spacing of the traces on the edge are set, and the max voltage and current are based on that. The width/spacing of the traces inserted into an edge connector are based on tolerances.
Trace fingers too wide, and a trace can violate spacing from the socket connectors on either side. Or even short to it, if all the other tolerances are at their worst. You can slide an edge connector a little bit left-and-right or you'd not be able to get the card in, that clearance has a tolerance.
If the trace fingers are too narrow, then they might not make full contact with the socket connectors and the connector specs for current will no longer be valid.
A particular pin-pitch edge connector will have a maximum voltage and maximum current per line. If you need more current, you parallel more lines. If you need more voltage, you use a different connector.
Steve Greenfield