I am working on a project that requires a step-down converter from 12V to 5V, that will then power a WeMOS D1 Mini. I saw this new mini buck converter based on the usual LM2596 MP2307 , so I thought I'd give it a try. Unfortunately, it didn't work. Although it is supposed to be able to supply up to 1.8A, the D1 Mini was not able to boot up. The 5V pin was being properly supplied, but the 3.3V pin measures at only ~1.3V. So I had to go back to my usual LM2596 module, which is much larger, but works to power the D1 Mini with a 12V source. Here's a great review of the mini buck converter I found while trying to figure out how to make it work. The fact that it has high quiescent current (~60mA) is also mentioned in a few other sources.