Please may I put this here, it is related to the above?....
Hello,
We have a 45W, non-isolated , offline product which has failed conducted differential mode EMC as per the following scan (attached). The product actually has no AC mains filter whatsoever, or even any capacitors on its DC bus.
We have thereby designed the attached AC filter which we wish to use to address this.
The problem is that I have just noticed that the 470uH inductor (DR0608-474L) has a SRF of 2.8MHz.
Can you confirm that this almost certainly means that we will still fail due to the >2.8MHz noise frequencies getting through the interwinding capacitance of this inductor?
Can you state any good ferrite beads that we can use in series with this 470uH inductor to be able to mitigate this?
(LTspice AC simulation, schematic and EMC scan attached)
Also, do you know of any good little "potting boxes" that we can mount this filter in? (it will be on a little piece of stripboard)..And also do you know of any potting compound that we can use to cover this filter PCB in the potting box?...we will just have the 4 wires coming out of the potting box then we will pour the potting compound in there. (we need to pot it otherwise the live mains connections will be open to touch.
DR0608-474L 470uH inductor datasheet
https://www.farnell.com/datasheets/...9.2079023285.1495515712-1679746183.1489787856
PR03 resistor datasheet
https://www.vishay.com/docs/28729/pr010203.pdf
(the filter has more attenuation than needed because it was originally designed for our 150W product which needed the greater attenuation...(however, we downsized the current rating of the 470uH inductor to make this 45W version cheaper and smaller)