There have been questions regarding connection of grounds of an isolated DC-DC converter. However I could not find anything that discusses whether the two grounds (when connected) should only be connected at one point.
I have connected the input and output returns of the isolated DC-DC converter using a jumper at a single point, and consequently created two split grounds on the bottom layer (as shown in the image of the layout). Is this advisable? Just to be clear, there are no other analog circuits on this board (ADC, DAC, etc), only the typical components that accompany a DC-DC converter: fuse, TVS diode, filtration caps, and LC filter.
Thank you!
Best Answer
It's fine to connect like that, it just means you will have a non-isolated converter.
A single ground-plane should be fine too since this is just a power-converter board. The usual reasons for a split ground plane (or more generally, a star topology of grounds) are where you have different signal-types in different circuit blocks and you want to ensure that ground-currents in one block do not induce a voltage in the ground of another block.
You may find that it's cheaper to buy a non-isolated converter though than to make one from an isolated converter.