I have a customer who is experiencing failures on an AM26LS31 on multiple boards.
The signature is somewhat different on different boards, but associated
symptom is the differential outputs not being in sync with the other.
C+/C- are the differential signal names on the AM26LS31 in customer application that are causing issues.
The board in question is from a subcontractor, so which specific pins on the device are not known at this time.
In one case, C+ drives high and C- drives low. C- returns to high
level. However, the C+ signal drives to an intermediate voltage for
about 1ms before going back to low level.
In another case, C+ drives high, while the C- does not change state.
This event is random, and not easily duplicated.
The primary question is related what types of events could cause this behavior with this device? EOS damage? Noise?
I would not expect a differential pair to be able to drive in this manner.
I have attached 2 scope plots of different signatures.
Thanks
