Is it possible for an IC to create a short to GND internally? Perhaps applying to much heat during the soldering process, supplying power to the wrong pins, mishandling, etc.?
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8Yes it is possible. – Andy aka Sep 05 '21 at 17:51
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7Completely possible. In fact, semiconductors tend to fail short more than open (I have never seen one fail open unless it exploded and was no longer there). – DKNguyen Sep 05 '21 at 17:59
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6@scottc11 `is it possible?` almost always has a `yes` answer – jsotola Sep 05 '21 at 18:32
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4It's more than possible, it happens all the time. – Hearth Sep 06 '21 at 05:32
2 Answers
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Yes, they can.
CMOS ICs if not properly designed are particularly susceptible to latch-up conditions whereby the intrinsic body diode in one or more of the FETs starts to act effectively like a thyristor and become a short circuit between VCC and GND supplies (*). Even if properly designed this affect can still happen in certain conditions.
Thermal damage from over-current (due to design mistakes, latchup conditions, etc.) can melt the delicate traces within the device and cause both open circuits, and also potentially short circuits - for example if the molten metal solidified across other traces (remember they are tiny and close together!). Such blown traces could result in say a PMOS or NMOS in a CMOS pair being left permanently turned on (e.g. if injected charge remained on the now disconnected gate), meaning the power supplies short when the other half of the pair is turned on.
Over-voltage can cause breakdown of the very thin oxide layers used for MOSFET gates (or between metal routing layers) and cause short circuits. Similar effects can happen to diodes where over-voltage causes a punch-through condition (related question) - this is particularly seen in the case of ESD protection diodes on IO pins when exposed to a high voltage discharge.
(*) Such latchups can frequently be ended by fully powering down the device
Tom Carpenter
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2Due to the whole micro-controller shortage, I have had to transfer an MCU (the IC in question) from prototype to prototype. Based on your answer, perhaps the repetitive soldering/desoldering of the IC (using a heat gun) melted some traces internally? – scottc11 Sep 05 '21 at 18:29
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@scottc11 Do you wear anti-static ESD grounding straps during soldering? Use a Cu braid for desoldering, if the package allows it. Heat guns are, well, heat guns. – Syed Sep 07 '21 at 08:05
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@Syed I have never used the anti-static ground straps. I have a set on my bench but find them a bit overkill ♂️ - have you ever fried an IC via static? – scottc11 Sep 09 '21 at 12:33
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1RF chips in developments many, some uCs, driver chip never. Touch the ground port of any equipment and you don't need a strap, but remember not to forget. – Syed Sep 11 '21 at 12:31
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Yes, it's possible.
Imagine some pins of the IC have clamping diodes for protection. If you apply the supply in reverse then these diodes will get short and ultimately your IC will have its Vcc and GND pins shorted.
PS: If you are measuring this Vcc-GND short on an assebled PCB then maybe you should also check the ceramic capacitors.
Rohat Kılıç
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