PF0100 VSNVS output voltage <3.0V

[zi-jian_chia4]

Hi,

I am troubleshooting three CPU module which failed to bootup due to the VSNVS output voltage is <3.0 V. Three units have different VSNVS: 2.0 V, 1.8 V, 1.63 V. I have tried to replace a new component on one board but the output voltage of VSNVS is still 1.8V. The supplied voltage to VIN is 3.3V.

I understand that the PMIC when powered by VIN, VSNVS is an LDO capable of supplying seven voltages: 3.0, 1.8, 1.5, 1.3, 1.2, 1.1, and 1.0 V. The bits VSNVSVOLT[2:0] in register VSNVS_CONTROL determine the output voltage and the default setting of the VSNVSVOLT[2:0] is 110, or 3.0 V, unless programmed otherwise in OTP.

I used PMIC (MMPF0100F2AEP) with imx6 dual lite SoC (MCIMX6U5DVM10AC) in my CPU module. The PMIC is pre-programmed  (F2 configuration) and I don't use coin cell, just a 0.1uF capacitor connected to LICELL.

Any input on why the VSNVS voltage is < 3.0 V although VIN supplied to PMIC is 3.3 V?

[guoweisun]

hi

Could you please show your PMIC schematic and all related circuit part for VSNVS?

[zi-jian_chia4]

Hi, 

Please find the schematic of P0100 to iMX.6 dual-lite. Note that this is a working schematic and I am troubleshooting the failure module return by customer so there must be some bad components in this circuit. 

I have tried replacing a new PMIC but the output voltage at pin 43 is still 1.8 V.

Any idea on how to look for bad components in this circuit that cause VSNVS unable to get 3.0V ?

Thanks.

Rgds,

ZI Jian

[guoweisun]

Hi

I suggest your disconnect with the 0Ω resistor then test the VSNVS only in PMIC side.

[zi-jian_chia4]

Hi, 

I removed the 0 ohm resistor and measure the VSNVS at PMIC side, the voltage is 3 V. PMIC is not defect.

I have also measure the VSNVS current  and it is 2.5mA which exceed imx.6 SoC maximum supply current.

Can I determine the SoC is the faulty part?

Thanks.

Rgds,

Zi Jian

[guoweisun]

HI

Sorry that I can only tell you that PMIC works well no issue,but more I.MX issue please submit other question to related community zone.