Burnt

Guest

Hi ,
I have a big doubt here .
My project is using a lot of E-pad QFP packaging IC .
I alway see this IC burnt , but from physical , I can't get to know this burnt is due to Internal short causing EOS Burnt , or External short causing EOS burnt . Further the external can be visual short underneat the IC (after mounting) & over voltage/current from external causing burnt.
Would it possible to determine the rootcause of burnt from physical ?

Posted: Tue Mar 22, 2026 9:24 am Post subject:

Hi PCBA FA Engr,

It is not possible to determine with absolute certainty the root cause of an EOS damage based on external visual inspection alone. You need to perform a full FA on the samples affected to be able to make a good conclusion as to what's causing the problem. Curve tracing, Internal Visual Inspection, Microprobing, and EOS simulations will provide useful information in determining the root cause. A good analysis of the EOS current path using a die schematic and its die plot is also needed.

Are you sure that your application board design is OK? Have you been using this board for a long time already with no issues? If it's a new board then I suggest that you recheck how well it was designed in relation to the product specs of the device you're using. Make sure also that you are not exceeding any of the max. limits for the device.

Good Luck and keep on posting.

EE

Joined: 20 Jun 2026 Posts: 76

Are you using units from the same lot? If so, then another possibility is that you got a lot whose devices have an internal weakness that causes the EOS failures. Examples: weak dielectric layers and masking issues.

However I also suspect that this is an application issue. Pls check all the possible conditions that the parts are experiencing in your board. You may be overlooking the transients or any transition periods. You really need to scope this out thoroughly.

FARel Engr

Guest

I think, to induce a visible burnt on the package - a very high (or surge) of current was needed.
If the high current source is continuous, the (gold)bondwires will fused open. As a starter, you can do X-ray to check for any wire abnormality.