I have an ADuM5000 that I want to run the input at 3.3V and get 5V at the output. The data sheet says this is not recommended, but I tried it on the bench and it made 5V, can I use it this way.
It will work under very limited conditions in this mode, but it is not robust or predictable so we do not recommend it. We had to make some design choices about what modes we could support. We could not do them all with good efficiency, but we could do 3.3V/3.3V, 5V/3.3V, and 5V/5V with one transformer design and good efficiency on all. The transformer turns ratio we chose is almost 1:1 so it does not step up the voltage a lot. When the output is set for 5V and only 3.3V is provided at the input it can make the voltage with no load at room temperature, but it will go out of regulation at relatively light loads, it gets worse with higher temperature, and the efficiency is terrible.
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