Hi Toby:

1) Does "failure" mean a) "stops working but will come back to life with
power and/or software reset" or does it mean b) "damaged"?

2) Is this a system-level test?

If it is a system-level test and 1a is true, then you have a gross system
level problem such as non-repeatable shielding performance of chassis,
poorly connected video cable, screws or conductive gaskets left out, etc.

Less likely - perhaps inconsistent operator test method - air discharge ESD
has been extensively researched and has many uncontrolled parameters which
leads to poor repeatability from test to test. But 1kV versus 25kV is so
huge a spread you would really have to be trying to mess up on purpose :-)

Best Regards

Lee

 
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Toby Carrier
Sent: Friday, July 17, 2009 1:51 PM
To: [log in to unmask]
Subject: [TN] ESD failure difference between 16-QSOP and 16-SOIC Video
Buffer

Hi,

Does anyone have an idea why a 16-SOIC Video buffer would pass ESD 
testing with being kludged in, compared to a 16-QSOP package of the same 
part actually soldered to the PCB? The SOIC part passes a Chassis and 
Common ground Air Gap event up to 25kV, but the QSOP part has failures on 
both chassis and common at 1kV and less? I would appreciate any articles or 
explanations that you might have.

Thanks

Toby Carrier
Engineering Technician

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