Getting the EMI Peaks : MMPF0100F0AZES

[pratikpanchal]

Hello Team,

We are getting the EMI peaks between 30MHz to 600MHz from the PMIC. The major peak is 357MHz.

Here is the schematic design (PMIC.pdf) for your reference.

Also, I have attached the snapshot(tek00031.png) for EMI peaks for your reference.

Kindly let us know the work around for the same ASAP as we are blocked in the final FCC certification.

[pratikpanchal]

Hello @guoweisun 

I have few queries

1) What is difference between MMPF0100 & MMPF0100Z chipset.?

2) What is default switching frequency of MMPF0100 & MMPF0100Z ?

3) Which value do we needs to configure for changing the switching frequency?

[guoweisun]

1.PF0100Z version differences in the PF0100Z datasheet page4

2: 1MHz is default switching frequency of MMPF0100 & MMPF0100Z .

3;Which value do we needs to configure for changing the switching frequency?

[GW]SWxFREQ[1:0]

[pratikpanchal]

Hello Team,

I Captured the switching waveform of all the switcher.

Kindly have a look and let me know its desired results or not.

[pratikpanchal]

Hello @guoweisun

I have near field probe in-house. So whenever I hover the probe over the PMIC then only I am getting this noise.

I checked full board this much of noise only generated by PMIC only.

Where exactly you are suggesting adding a common mode choke in the design?

[guoweisun]

Add common choke at the VIN terminate of PMIC to try.

[guoweisun]

In the PMIC input rail add common mode choke,for the detail value you should try by test.

[guoweisun]

The PMIC switch frequency is up to 1-2MHz,but in your EMI issue test up to 600MHz,how do you know this issue caused by PMIC?

You should add common mode choke to solve this issue in system circuit.