--- In
Homebrew_PCBs@yahoogroups.com, Stefan Trethan <stefan_trethan@...> wrote:
>
> If you'd actually had a look at the datasheet I linked to you'd see
> the recommended _MALE_ pattern in there, including clearance for this
> particular connector. It's always like this, the female connector
> prescribes the pattern for card edge.
Since I did actually look at the first link you gave:
http://www.edac.net/file_library/series/39_737.pdf I saw that on page two it did -not- show the width of the male edge connector -traces-, nor did it give the spacing between them. You cannot infer that from the pin pitch. Do you really think I'm so dim that I can't figure out that 0.1 inch pitch socket means 0.1 inch pad spacing on the card edge?
The spacing between the traces of an edge connector are based on tolerances. Too close together and you run the risk of cross-connections if all the tolerances are at their worst. Too far apart (therefore too narrow) and there may be less contact area and therefore the specs for current ratings are no longer valid.
> Since you seem to be talking specifically about the ISA slot, here are
> the mechanical dimensions:
> <http://www.xs4all.nl/~ganswijk/chipdir//////oth/sokos/isa.txt>
Thanks! That one gives what I need, pad width of 0.060 +-0.005 on 0.100 +-0.005 inch centers.
It wasn't that I need to make an ISA card, but that I was trying to be clear about what I was looking for. And that is an official specification I can point to when my instructor asks for justification for the 8 to 12 finger edge connectors on my assignments.
> The correct publication would be IEEE-P996, but since it never got
> finished it is hard to get. Probably the original IBM PC
> specification, or even earlier telecom specifications (from which the
> ISA slot was inherited) will also have the dimensions.
>
> If that isn't "official" enough I again suggest to go by what your
> socket manufacturer says. For example this datasheet of the ISA
> connector has _again_ the recommended male finger pattern in it.
> <http://www.hirose.co.jp/cataloge_hp/e54801112.pdf>
That one shows what the link you gave in your other email did not, pad width on page 5. Thank you.
> All this information was easy to find in 5 minutes with google. I put
> it down to stress while finishing your project.
>
> ST
Wow, after all this time... So doing the work, then asking for help isn't enough now? Are members here subject to your scorn simply for asking for help at all? Are you trying to say I didn't try looking at all before asking?
Yes, I am very stressed. I've got until the 17th to turn in everything. I was not warned that the second from the last chapter in the last book has more work in it than the entire rest of the book. I was left to find a schematic capture/PCB program on my own. With five days left, I discover that the program I've chosen seems to be unable to handle an edge connector, and now have to find another program and hope I can learn it well enough -and- that I don't find out I have to start over again in a day or two.
Steve Greenfield
> On Sat, Feb 13, 2010 at 12:57 AM, alienrelics <alienrelics@...> wrote:
> > All that tells me is how deep the socket is, and the pitch. I can find diagrams for the sockets all day. I know the pitch, because I select it. What I need to know is the clearance between pads. And I can't eyeball it, this is for a class and we are specifically not allowed to "eyeball" or estimate anything. I have to show where I got my numbers.
> >
> > If this were for my use only, I could toss a board under my microscope with a ruler and estimate it very closely.
> >
> > Heck, this book I'm working out of is pretty old. Most of the assignments require 20/20 rules for logic and small signal analog.
> >
> > Thanks,
> > Steve Greenfield
> >
> > --- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan <stefan_trethan@> wrote:
> >>
> >> The correct pattern is determined by the mating connector. You should
> >> find the recommended pattern in it's datasheet, like this for example:
> >> <http://www.edac.net/file_library/series/39_737.pdf>
> >>
> >> If there is nothing in the datasheet for your connector ask the
> >> supplier, or eyeball it. There are some differences between the
> >> different brands of connectors, some have one contact, some have them
> >> split in two, etc..
> >>
> >>
> >> Remember that gold plating the edge connector usually requires you (or
> >> the board shop) to extend the tongues out and run them together in a
> >> shorting bar, so they can be contacted for gold plating. Have a look
> >> at an extremely bad image here:
> >> <http://t2.gstatic.com/images?q=tbn:d91SlFCXorXWaM:http://www.ettech.com.tw/English/picture/FR-4,%20Edge%20plating,%20Sink%20Milling,%20Medical%20PCB-1%20.JPG>
> >>
> >> ST
> >>
> >>
> >> On Fri, Feb 12, 2010 at 6:09 PM, Steve Greenfield <alienrelics@> wrote:
> >> > I've done quite a bit of Googling, and all I find are diagrams and measurements of edge-connector sockets. Or just the outer dimensions of the PCB edge-connector. I am looking for the specs for trace width, spacing, and length.
> >> >
> >> > Any ideas?
> >> >
> >> > Thanks,
> >> > Steve Greenfield
> >> > Electronic Engineering Technician student
> >> > Electronic Technician 20+ years
> >> > CET Computers and Consumer Electronics
> >> > IPC-A-610D CIS Specialist
> >> >
> >> >