About this component
Drops the VIN pin supply (7–12 V recommended) down to 5 V for the MCU and anything on the 5V pin; it is bypassed when the board runs from USB. It is a linear part, so a high VIN with a heavy 5 V load makes it hot. If you swap between LM1117/AMS1117 and the older 78M05, check the pinout first, because pin 1 differs. Part variants: Nano v3.2 and later use an LM1117 5 V regulator; v3.1 used a TI UA78M05 (different pin order: pin 1 is VIN). AMS1117-5.0 is what most clones fit.
What it does on this board
Regulates VIN down to the 5V rail.
Pinout & readings
Pinout and readings are for members
Create a free account to see the test data for U2 (LM1117-5.0):
- The full pinout — 4 pins with what each one does
- Datasheets