How we tackle Functional Test
Why connectors are the way to go for functional test.
While shorts on connector pins are a problem, these are easy to find. Opens are the manufacturing defect on connectors that make OEMs lose sleep at night. More technical diagnoses for opens include cold solder, no solder, lifted pin, etc. These can be caused by a variety of minor processing, handling, or supply-chain issues.
But why not use flying probe or clamshell?
Drawbacks to Flying Probe or clamshell
Pogo-pins such as Flying Probe or clamshell fixtures can fully test connectors that are:
Rugged.
Pointed in one direction.
Not subject to false pass under mechanical load.
A Not subject to relocation due to design changes.
Pogo-pins must press the connector pin against the board. This is not a test feature with options but a law of physics affecting all pogo pins because they are spring-loaded. In the case of an open defect, the pogo pin can force the connector pin to conduct only during the moment it is tested – a false pass. This test challenge affects all surface-mount connections. While some through-hole connections can get excellent coverage using pogo-pins, these connectors are often presented to the user. In this case a test-mate to check for bent pins and mechanical defects can avoid embarrassing Out-of Box Failures.
Why we go with connectors
The only way to guarantee the performance of the connector is to test through the connector.
Also, when cables are selected for the UUT connection, it opens up cost savings opportunities regarding test coverage. Connectorized test allows the fixture to be constructed in an open-frame fashion allowing your technicians to diagnose failing boards by probing with their oscilloscope or multimeter. This means the functional test code can focus on a top-level PASS/FAIL result drastically reducing the amount of code required for the test. Clamshell fixtures just don’t offer access to human measurements.
If you want to learn more about Functional Test, click the button here to read.
Contact CAE Integration today for a test plan optimized for your specific product.
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