Electronics > Microcontrollers

Two ATtiny406 dead within a month????

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bidrohini:
Very disappointing, no doubt.

PinheadBE:
A bit off topic:
If the goal of D24 is a reverse-polarity protection, I should have placed it AFTER the polyfuse

Just my 2c...

PCB.Wiz:

--- Quote from: satyamfifa on December 06, 2022, 06:18:32 am ---...
So now I am puzzled I don't know what could be killing these ATTinys.
Also, it's worth mentioning that System VCC is 5.4V, although I don't know why this should be a problem.
..
... Update: Three Chips are now dead
..
Also, it's worth mentioning that at the time second one died I was continuously connecting and disconnecting the programmer as well connecting and disconnecting the power to the board.

--- End quote ---
The OP may have solved this already, but I'll add that connecting and disconnecting the power to the board. needs care.

A couple of years back we had a few Atmel parts fail on board final test, and we tracked that to the live power connection of a bench power supply.

We added a wirewound 2r2 series R, and no more problems.

It seems the abrupt connection of an already charged power supply, gives very high dV/dT to the wiring and PCB and that was enough to literally  spike things.
Normal power on/off does not have the same extreme rise times.

Some useful waveforms showing hot-swap / live-connect effects are here :
https://www.analog.com/media/en/technical-documentation/application-notes/an88f.pdf
and here
https://www.ti.com/lit/pdf/slva703

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