Retronix Blog

Jun 20, 2017

An OEM was trying to buy 5k of an IC that was obsolete. They were offered the parts from Asia.


IC_Test

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
Box Damaged
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

Pin-Marking1

 

 

 

 

 

These were ok

Then an inspection of the body/leads carried out, looking for cracks, contamination etc

Figure-5-Side

Again this was ok.

Then a heated solvent test revealed no blacktopping and change of markings.

Heated-Solvent-Test


Next thing that was done was a decapsulation on one part where the component body is etched away to reveal the die –

Decapsulation

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
X-Ray Testing

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.

 

KFT-Blog

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.

 


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