Unexpected DC Voltage on VGEN5

[nicholasschmidt]

PMIC MMPF0100F0ZES

We have VCOREDIG connected to VDDOTP through a 100k resistor for the default configuration, from which we expect to see 2.5 V on VGEN5 per MMPF0100Z Rev 9.0, 12/2015

However, when we power up we see ~3.1 V on this rail.

Is it possible that something in the HW design is causing this issue?

Is the datasheet incorrect?

[Yuri]

Hello,

1.

The recent PMIC Datasheet may be found at

http://cache.nxp.com/files/analog/doc/data_sheet/MMPF0100Z.pdf?fpsp=1&WT_TYPE=Data%20Sheets&WT_VENDO...

2.

  You are right, for  default configuration for VGEN5 (VCOREDIG connected to VDDOTP through 100k),

it should provide 2.5 V.  Please check the design regarding PMIC erratum  ER19.

http://cache.nxp.com/files/analog/doc/errata/MMPF0100ZER.pdf?fpsp=1&WT_TYPE=Errata&WT_VENDOR=FREESCA...

Have a great day,
Yuri

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[nicholasschmidt]

Hello Yuri,

1) Thanks for the datasheet link.

2) I don't think this error applies. The regulators that I expect to start up all do. The issue is overvoltage on one of the regulators. However, I have tried connecting LICELL to our main 3.3 V supply (it is the first supply up on the board, and also feeds the PMIC) to bypass this issue--the change had no effect on VGEN5's output voltage.

3) I have found something else: the VCOREDIG and VDDOTP pins are at 2.7 V instead of the expected 1.5 V. The only component connected to these pins is the 100k resistor joining them.

Regards,

Nick

[Yuri]

Hello,

  Let me look at the scheme (the PMIC and all its power consumers).

You may create request for it : How to submit a new question for NXP Support

Also, please provide PMIC photo with its part number.

Regards,

Yuri.