PMP8878: input DM CM filter

Hi Anoop,

Your E2E post was only just today brought to my attention and let me start by apologizing for the unacceptable long delay you've experienced. E2E threads are most easily filtered and assigned to experts according to TI part numbers listed in the title or thread body. Since your post did not include a part number, I believe this was partly why it went unnoticed. This needs to improve from our side and again I apologize that your question did not receive the response it deserves within the 24 hour time frame TI strives for.

For a fixed frequency converter topology My approach to EMI filter design is to first pass conducted emissions (CE) according to whatever standard you are targeting. If you have access to a CE test setup and spectrum analyzer, you should first measure the ambient environment (nothing switching) then measure the unfiltered emissions of the converter to determine which frequencies should be targeted by your EMI filter design.

If you have not yet designed the converter and want to add placeholders for EMI components to be tested, I've attached some excellent TI resources addressing CM and DM filter design and practical tips for mitigating EMI during test. Also here is a link to TI's Engineers Guide to Low EMI in DC/DC Regulators. Some of the EMI filter component vendors have also made available some excellent online simulation and design tools for EMI mitigation. Two that I have been evaluating recently are Simsurfing from Murata and Redexpert from Wurth. You may have to register to use the full features offered. TI Video Training Series is another resource you may find helpful - many of the offered videos are targeted for specific end equipment (automotive, industrial, motor drive, POL, etc), design tips and EMI standards.

I hope some of these resources help to answer your E2E and again, I apologize for the late reply. Thanks for your interest in TI products and please continue to post and share your expertise through TI E2E?

Regards,

Steve M

Bing Lu_Introduction to EMI in power supply designs.pdf

slup400.pdf

slyp679.pdf