I have some 150V traces on a circuit board that's being controlled with 5V logic and op-amps. For the higher voltage lines, I have the ground piped through the boost converter so I have a controlled path for the return current. I wanted to keep everything as low noise as possible and felt that the return for something like this going under my analog circuitry would be bad news. They both share a common ground, but that just doesn't meet until the input (star configuration). I also wanted to isolate the switching boost converter as much as possible.
How much isolation is enough? We're talking about <1mA of current and I've setup a solid 15mil isolation but I just wanted to be that it's enough before I had it made. This is the first time I'm working with voltage this high and wanted to be sure to keep noise to a minimum.
Any advice?