PMIC MC34708 : VSRTC not OK with coin cell connected and power OFF

[jomeke]

Hi,

in an application we use the iMX537 MCU which is powerd by a PMIC MC34708. Until now we produced a 1000 boards without any problem.

With the last batch of boards (250 pieces) we have a problem on 10 boards with the coin cell back up.

There is a 3V coin cell connected to the PMIC.

When the power is applied (BP = 3.8V) VSRTC = 1.3V --> OK

When the power is removed and the cion cell has to take over, VSRTC drops down to 0V.

We have replaced the PMIC on 3 boards and the problem was gone.

That looks like the PMIC is bad, has anybody experience the same problem ?

Could there not be an other reason for that behavior ?

[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

-----------------------------------------------------------------------------------------------------------------------

Note: If this post answers your question, please click the Correct Answer button. Thank you!

-----------------------------------------------------------------------------------------------------------------------