DCR010505: DCR010505U: EMI - Conducted Emissions

Hi Boom,

Conducted Emissions (CE) measures the input voltage and current ripple spectrum.

For Conducted Emissions (CE) input filter, we recommend a CLC PI filter with corner frequency of 40kHz this will filter the differential (DM) mode noise.

Try that first, then check if you need to add a common mode (CM) choke filter as well for the higher frequency harmonics.

Background:

The DCR010505U uses a push-pull topology switching at 400kHz.  This means input switching ripple and current is at 800Hz (2x400kHz).  You will also see the harmonics of 800kHs on the spectrum measurement.

The 800kHz switching ripple is seen on the input current reflected ripple in Figure 7-17 of the datasheet.

DCR01 Series, 1-W, 1000-VRMS Isolated, Regulated DC/DC Converter Modules datasheet (Rev. E)

Here are some links for more info on CE and filters

Practical EMI Considerations for Low-Power AC/DC Supplies: Introduction to EMI, DM vs CM | Video | TI.com

Input Filter Design for Switching Power Supplies

Hope this helps you pass your EMI testing. 

Hi Boom,

You can send your question directly to my email: r-martinez3@ti.com

Hey Robert,

I've sent an email. Thanks.