Whether it be a initial prototype or a production unit, performing signal integrity tests is very important.
- Especially, during the signal integrity performed on random production boards, we have to compare the results with simulations and initial prototypes
- Use the coupons on the board to perform tests - tests can be any of these as per demands of the test cases defined in production -
- Continuity
- using TDR to measure impedance
- using Hi-Pot test to test the isolation between trace and dielectric
- peel test to measure the force required
- propagation delay of the trace,
- insertion loss (using Vector Network Analyzer at highest possible frequency)
- return loss (using Vector Network Analyzer at highest possible frequency)
One might ask, do we need to perform all these tests on all the boards? No, at least for the initial set of boards perform all the tests and later do a random sampling. But these tests are definitely mandatory, especially if this is first set of production lot. For future production, random sampling can be done for testing. Also, these tests are necessary, if the FAB house is changed in between the production lots or some reason. One thing is clear, the role of signal integrity engineer is very critical till production boards closure.
]]>
0 Comments