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[FIXME: more tips on testing electronics, and building test jigs to help test them, need to go here ... pointers to test tools from simple LEDs to spectrum analyzers ...]
Subject: [PROTEL EDA USERS]: Test fixture design From: Bob Puckette on 2000-08-23 11:07:57 AM Please respond to "Association of Protel EDA Users" <proteledausers at techservinc.com> I've come up with a cute way to generate pogo pin test fixtures. It's been working so far, but I'd like to see if anyone has any contructive criticism for the scheme. It goes like this: 1. Take a copy of the final artwork and delete everything but the tooling holes and the test pads. 2. Do a global change to change all the test pads into thru holes that will accomodate pogo pin sockets. 3. Route all the pogo pin sockets to whatever you test with on a bigger board that the production board. This is an easy job for the auto router. 4. Have a cheap quickturn fab (I use PCB Express) make two copies (a minimum order) of the board. The idea is to use stand-offs to make a pogo pin block out of the two boards. The pogo pin sockets will be held reliably in parallel by the sandwich of the two boards. 5. Cram rod stock through the tooling holes and, viola, you have guaranteed registration of all the pogo pins to the DUT. 6. One of the test boards is populated with connectors, and whatever test circuit you want up close to the board. My designs usually have a bunch of connectors to an Agilent data acq system, and a bunch of relays. This seems to me to be easier than getting the pogo pin block machined and then wiring point-to-point to the testhead. Any comments.... Bob Puckette 345 SW Avery Ave Corvallis OR, 97333 541.752.9000
The traditional test fixtures have individual wires run from each pogo pin to the test instrument I/Os. (see "Getting On-Board ATE Test Fixtures" http://www.evaluationengineering.com/archive/articles/0304/0304ATE.htm by Tom Lecklider for some nice pictures ).
More recent "wireless" fixtures have a "test" PCB, similar to the one described above, but with traces on the PBC running from the PCB to the test circuits, which may be on the same test PCB. See "Wireless Test Fixture Considerations" http://www.ectinfo.com/files/resource/technical/wireless_test.html by Gary St. Onge and Jeff Sendzicki , CIRCUITS ASSEMBLY, June 1998
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