An OEM was trying to buy 5k of an IC that was obsolete. They were offered the parts from Asia.
An OEM was trying to buy 5k of an IC that was obsolete. They were offered the parts from Asia. They did not know the supplier, so they bought them on escrow, giving them time to investigate before handing over the money.
First thing that was done was to investigate the packaging :
|ESD Protection – were they in an ESD bag?|
|Poor Syntax or Alterations on the labels|
|Correct MSL Packaging|
|Quantity Matched Documentation|
|Type of Package|
All of the above was in order.
Then a full visual inspection was carried out, to see if the components were obviously used or counterfeit :
First the pin 1 marking and the country stamp on the bottom were examined to see if they had been altered
These were ok
Then an inspection of the body/leads carried out, looking for cracks, contamination etc
Again this was ok.
Then a heated solvent test revealed no blacktopping and change of markings.
Next thing that was done was a decapsulation on one part where the component body is etched away to reveal the die –
This was a good start as it revealed the die markings were correct. However more work was needed to test the whole batch were original, and without other issues.
The complete batch was then x-rayed to ensure the bond wires etc were exact
Again this revealed the components were as they should be.
For electrical test a curve trace was deemed unnecessary due to the small amount of connections. A Key Functional Test (KFT) to test the main parameters of the chip was seen as a better option.
This again came up well across the whole batch
Then a solderability test was carried out which revealed oxidisation. As the terminations had been inspected and found to be fine, this was deemed to be the only fault and caused by the components being old.
So they were retinned in Sn/Pb to remove oxidisation
An XRF test was then deemed unnecessary as the alloy was known then to be correct.