MC34708 : VSRTC not powerd by the coin cell

[jomeke]

Hi all,

on one of our boards we are using the iMX537 which is powerd by the PMIC MC34708, on the PMIC there is a 3V coin cell connected.

Until now we produced approximately 1000 unit without any problem.

With the last batch (250 pieces) there are 12 boards with the following failure :

When the power is applied : VSRTC = 1.3V --> OK

When the power is removed : VSRTC drops down to 0V.

So the connected 3V coin cell doesn't take over to feed the VSRTC supply.

We have replaced the PMIC on 3 boards and the problem is solved, so it looks like the PMIC chips are bad....

Has anybody experienced the same problem ?

Could there be an other reason for that behavior ?

Thanks for the respons

[igorpadykov]

Hi johan

I had not heard about such issues, but think

that this may be caused by technology process:

solder overheating or ESD handling. In general it may

be recommended to send chips for quality analysis

through marketing local office.

Best regards

chip

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