Has anyone used Diodes AP62300 (or 62200, 63300, etc)? It's a cheap/simple buck converter with internal switch. I designed a board based on Figure 1 of their datasheet. Albeit my component values differed a bit. My values were as follows:
C1 22uF (this was actually part of a Pi filter, so there were 2 22uF caps with a 10uH inductor in between).
C3 1uF
R1 52.3k (with 47pF in parallel)
R2 10k
L 10uH
C2 2x22uF with a diode between them. There is also a 1000uF electrolytic in parallel with the 22uF on the cathode side of the diode.
When I power the circuit up, it starts drawing current as if its a resistive short between power and ground. I have four different boards, they all do the same thing although the resistance varies from about 5 to 20 ohms. Hitting it with a thermal camera shows the part as the only heat source on the board when I power up the input.
I don't think it's powering up the output. Nothing on the board seems active. The diode I mentioned on C2 has another parallel diode, effectively an alternate way to power the board up without going through the AP62300. When I power that side up, it draws about 90 mA @ 5V which is about what I'd expect. There is some inrush given that electrolytic, and my Riden 6006 power supply acts a bit goofy if I don't turn the current limit up a bit beyond the 90mA, but 150mA is adequate for it to start up correctly.
I've tried contacting Diodes Inc, but they are not being responsive.
https://www.diodes.com/assets/Datasheets/AP62300_AP62301_AP62300T.pdf