Attached are the datasheet, schematics and two design options for a switching supply boosting 7.2v to 12v,20mA. My question is intended to be general but I wanted to include my current project as an example. The first design is intended to have a return path shorter than the return path of the second design. I believe I understand the role switching frequency plays on the behaviour of the return path:
1. >MHz frequency and the return path is dictated by inductance.
2. <MHz frequency and the return path is influenced by resistance of the copper plane.
I've seen designs on forums before where a responder would jump on the design for having too long of a return path while it didn't look very long at all. Should I expect behavioural differences in the two layouts here? How would I determine how long is too long of a return path?
1. >MHz frequency and the return path is dictated by inductance.
2. <MHz frequency and the return path is influenced by resistance of the copper plane.
I've seen designs on forums before where a responder would jump on the design for having too long of a return path while it didn't look very long at all. Should I expect behavioural differences in the two layouts here? How would I determine how long is too long of a return path?