Wednesday, October 17, 2012

How to test STK795-813 IPM for defects

Half the STK795-813 ICs we received the last time from our vendor were defective.

Here's a short note I just wrote to them asking them to please save time and money and test the ICs before they send them in future.

This will also be of great help to all other US "vendors" who are not competent enough to do it on their own, which is probably the majority. No offense meant, that's what I see and hear from customers.

The test is not complete, meaning an IC may pass it and still be bad, but that will be one in a few hundred in our experience. It's a quick, simple and easy test which easily takes care of the most common failures.

BTW you can also buy STK795-813 - already tested! - at our store, for as long as supplies last.

And here is the text:

Here is a picture of the STK795-813 with the important pins:
(please forgive the bad quality - click to get a large view; I was on a rush)

You will usually be testing the IC looking from the top, but I only thought of that after I made the may want to make a drawing on your own if you want, just make sure to note that when you flip the chip upside down positions change symmetrically :-)
Testing is similar to the way you test the STK795-518, only the legs are different.

The testing device will still be in “diode” mode where if you touch the two probes it will beep to indicate short circuit.

In the test you will be touching different pins of the IC, not the two probes of the device.

But before starting you make sure the device is properly set up by touching the two probes for a moment. The device should beep.

You will make 3 tests on each IC.

If any of them results in continuous beep and reading of “0” (or the same reading on the display as you get when you touch the two probes of the meter and hear beep) then the IC is bad.

You will be testing:

1)      VS to GND
2)      VS to SUS_O
3)      GND to SUS_O
Each of the contacts (VS, GND and SUS_O) has multiple pins on the IC, i.e. all pins in the group are the same and it does not matter which one you will try on.

I do not know if the ICs I sent back have already arrived, but you can practice on them – all of them have at least one of those three combinations shorted.

Let me know how it goes.


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