ADUM5400 EMI reduction

Falk:

As detailed in the ADuM5400 datasheet:

"VDD1 power supply input provides power to the iCoupler data channels, as well as to the power converter."

Therefore, if you reduce VDD1 to 0V, you will not power the iCoupler data channels, as well as the isoPower output.  Is this what you want to do?  Can you show a block diagram of the ADuM5400s and the way you propose that you would wire them in your circuit?

Regards,Brian

Hello Brian,

see my two attachments. draft1 is the current setup. Both ADUM5400 are active. draft2 two shows my goal. IC9 is powered by IC5 on the isolated side, so only one ISO-Power Converter is active and generates noise, since I dont need the full power of one ISO-Coupler.

My idea was, that VDD1 powers only the ISO-Power converter and the data channes are completely powered by VDDL. I want to use all four channels on both ADUM5400.

Regards

Falk

draft1, current schematic

draft2, my goal

OK, I found a simple solution. I replace IC9 by an ADuM1410, which has four channels too and runs on 5V, except it has no ISO-Power converter. This way I reduce HF noise and save money.

Regards

Falk

Falk:

I agree that if you don't need the extra power provided by a second isoPower output , then you can use an ADuM1410 powered by one ADuM5400 VISO. You need to connect the 5V supply on the primary side to VDD1 of both ADuM5400 and ADuM1410 (just like you would have needed to connect the 5V supply to the VDD1 of each of the 2 ADuM5400s if you used them).

Regards, Brian