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ADuM 5000 proper parallel layout

Question asked by mrispoli on Jul 7, 2016
Latest reply on Jul 8, 2016 by DaveC

I am having some trouble with heat management while using some ADuM5000 chips to send isolated DC power across an isolation barrier. I have approximately 6 chips with one in a "master" configuration and the other 5 in a "slave" configuration. Or at least I think they're configured correctly. The RCsel is set H for the Master and L for the Slaves. The RCout from the Master is connected directly to all other 5 Slaves and the RCins. The Slave RCouts are not connected and the Master RCin is not connected. This was my naive assumption on what the correct parallelizing should be

for this design but the spec sheet also says something funny about the "RCout" for the slave chips which it says should be wired to "RCin". Does that mean actually just tie those two pins together or that they should daisy-chain from one chip to the next. I tried both of these and it caused the master chip to skyrocket in temperature. Without tying the RCout and RCin chips together for the slave devices then all the chips seem to get up to about 70C external temperature. The ADuM 5000's should be providing about 360mA at 3.3V on the isolated side and take a 5V input. I would've expected this to spread the load out along the chips such that they wouldn't heat up so much. Does this seem reasonable?

 

Separately are there any sample schematics of simply parallel DC-DC converter power boards that I can check my design against?

Thanks.

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