MMPF0100 programming and startup

[davidchesney]

I have the non-programmed MMPF0100NPAEP in my design, and I'm trying to get in running, but haven't gotten anything to work.  I'm using the default voltage setting (VDDOTP pulled up to VCOREDIG).

VSNVS is only at 1 Volt, but the default setting on the data sheet is 3V.  Is this a problem?

My understanding is that with a Vin applied, a pulse low on PWRON will cause the device to turn on all the outputs at the default voltages, but this does not happen for me.

Vin=4.2 V

VDDOTP pulled up to VCOREDIG

PWRON and SDWNB pulled up by VSNVS

[davidchesney · Accepted solution]

We've found our issue.

Our board was based on the Saber development board.  Although it was listed as DNP on the dev board, our design had the 10 uF capacitor populated that connected to VDDOTP and GND. This caused the PMIC to believe it was in the programmed state instead of the default state.

Once we removed this capacitor, the VSNVS would go to 3.3V as soon as a valid VIN was received.  LICELL still has no voltage applied.

[igorpadykov]

Hi David

you can start with checking application note AN4717 (Rev. 1.0, 4/2013)

"Schematic Guidelines for the MMPF0100", sect.2 "Schematic Checklist".

http://cache.freescale.com/files/analog/doc/app_note/AN4717.pdf

Regarding start-up MMPF0100 Datasheet (rev.8, 6/2014),

for  non-programmed version (MMPF0100NPAEP), Table 10 "Start-up Configuration"

defines PWRON as "Level sensitive" (PWRON_CFG = 0),

from Table 14 "PWRON Configuration" :

PWRON pin HIGH = ON

PWRON pin LOW = OFF or Sleep mode

from sect.6.4.2.1 "Turn On Events":

If PWRON_CFG = 0, the PWRON signal is high and VIN > UVDET, the PMIC will turn on

http://cache.freescale.com/files/analog/doc/data_sheet/MMPF0100.pdf

Regarding VSNVS, yes you can consider it as normal.

Its behaviour depends on many factors, described in sect.6.4.7 "VSNVS LDO/Switch".

Best regards

chip

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[davidchesney]

Thank you for the reply.

The VSNVS is not behaving as expected, as far as I can tell.  Vin = 4.2 > VTH1.  I have nothing connected to LICELL (also tried a 3V supply connected).

VSNVS is still in default state, so it should go to 3V, correct?

[igorpadykov]

According to sect.6.4.7 "VSNVS LDO/Switch"

for the very first time, VSNVS will output 1.0 V.

You should have connected LICELL, then when VIN is

applied thereafter will VSNVS transition to 3V.

[dnichols]

Hi Igor,

I work with David Chesney and we're still trying to troubleshoot/understand the situation. The way we interpret the above is if there's nothing connected to LiCell except for the 0.47uF capacitor, upon power-up we should expect 1.0V at VSNVS. If this is true, does this prevent the PMIC from turning on? We would be more than happy to send you our schematics if needed.

Thanks,

Daniel Nichols, P.E.

[igorpadykov]

Hi Daniel

no this should not prevent PMIC from turning on.

I think for schematic it would be better

to send it creating SR ticket.

Best regards

chip