UC2577 failed in storage?

[NiHaoMike]

I was working on a UC2577 based boost converter and the first time I tried to power it on, it drew a lot of current. After debugging, I found that the chip was internally shorted. After checking my circuit for faults that might have caused the failure, I replaced the chip and same problem. Then I took out a third chip (last one I had) and measured it before I even used it, and it was also bad.

How would three chips in a row go bad from storage? They were all stored in a piece of antistatic foam, so ESD seems unlikely. Moreover, other chips (including some CMOS logic chips) in the same piece of foam work fine.

[notsob]

not likely a bad batch, more likely someone wearing nylon undies handled them before they were sent to you.

[Mechatrommer]

more likely someone wearing nylon undies

technically speaking... just by touching or wearing that material wont do much harm. the wearer need a significant amount of "rubbing" with the material before she can build a dangerous voltage that can penetrate antistatic.

[notsob]

I was just trying to add some humour to the possibility of incorrect handling of the devices upstream.

I once worked for a company that moved from 'casual' component handling, to fully antistatic procedures, (floor mats, table mats, ankle straps, discharge points at every bench, anti static holding bins, you name it), obviously this was quite some time ago, their faulty on manufacture and 'dead' board returns during the first 6 months dropped by an astonishingly unbelievable amount.
So yes antistatic procedure are very important, and depending where you source your parts, there could be problems introduced upstream.

[SeanB]

Could also be a faulty batch, a fake one or a contaminated batch that failed with time.

[LaurenceW]

If you've measured a brand new part and found it to be short circuit, I would very much doubt that static could cause a low impedance short - if anything, quite the reverse (until you plugged a faulty part in to a current bearing circuit - then it might fail to short).

It does sound to me like you have manufacturer rejects or even fake parts. How do the markings look? Where did you buy them from ? When you say "short", between what pins and what impedance are you seeing? What is your circuit?

I have used these devices myself in the past, and not had any "Dead on Arrival" or subsequent demise problems. They can be unstable if not decoupled as per the spec sheet, however.

[NiHaoMike]

They were TI samples I ordered a few years ago for a self driving model race car. (First year class project.) They went unused because it turns out the control circuit was the bottleneck and boosting the voltage would not do any good.