0
\$\begingroup\$

I am working on a project that has LIPO battery and a USB as a power inputs. The system should use the battery but if the USB cable is plugged it has to use that as a power source instead of the battery.

enter image description here

The design is mostly based on Adafruit ESP32 feather https://cdn-learn.adafruit.com/assets/assets/000/041/630/original/feather_schem.png?1494449413. If I understand it correctly the MOSFET is turned off if V_USB is < than V_BATT.

I plan to have this board assembled by JLC PCB and both the MOSFETs and the Schottky diode are extended parts. I want to replace them by basic parts to make it cheaper so I'm looking for alternative parts, Are B5819W and AO3400A adequate replacements in this case?

\$\endgroup\$

1 Answer 1

0
\$\begingroup\$

AO3400A is a N-channel MOSFET while the DMG3415U shown in the diagram is a P-channel device. So, no, the AO3400A is not suitable as a substitute.

I don't see any problem with using the B5819W diode as a substitute. Given it's function in the circuit, it should do fine.

The AO3401A given in the comments is indeed a P-channel device and looks like it is suitable. It has a bit higher ON resistance at around 5Vgs, so it'll dissipate a bit more power but nothing significant.

\$\endgroup\$
1
  • \$\begingroup\$ You are right, AO3401A \$\endgroup\$
    – Marc
    Nov 1, 2020 at 19:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.