It’s a simple question, but I’m struggling to find the answer (on the internet or in the datasheet).
What happen if I connect a 5v power supply to the Vin of [this Sparkfun board?
I need to power a 5v microcontroller with a power source that supports 12v or 5v input.
Thanks.](SparkFun Buck Regulator Breakout - 5V (AP63357) - COM-21255 - SparkFun Electronics)
You’ll probably end up with slightly less than 5 volts out with 5 volts in, you will need to test your circuit with the board to make sure that it will work under those circumstances.
If your circuit can not tolerate a Vin less than 5 volts a buck/boost regulator is what you’re looking for. Pololu has one that should work.
The AP63357 datasheet says it has an LDO (low dropout) mode for 3.8V<Vin<5V, but doesn’t say what the voltage drop is. You will have to determine that experimentally.
Thank you for the answers!
I know I should try with one of the boards, but it is immediately inaccessible for me right now (for geographic reasons).
Look at this graph:
https://i.imgur.com/D1duMKB.png
Should I hope that the LDO output voltage is something around 4.98v? I’m OK with the output going down to a limit of 4.7v, is that asking too much?
Thanks!
It is pointless to guess. You will have to determine the voltage drop experimentally.
