So I purchased the JDY-10 BLE 4.0 module and a very small MCU which only is capable of feeding 5v.
Since I'm not an electrical engineer, I've been reading a bit on the internet, and so far, I understand that the Bluetooth module will be fried if I hook it up to a 5v power source. As far I can understand, a voltage divider is not usually the way to go, but would it be okay in this case? – I plan to put this on a PCB that I make on my own, therefore the solution should be fairly lightweight/simple.
Furthermore, would the RX pin require a pulldown resistor? (The datasheet doesn't reveal anything in that regard – and to be honest, I don't think it has one)
Best Answer
A voltage divider is okay to use for signals, but not for power as it either gives you a very high supply resistance or wastes a lot of power. It's better to use a voltage regulator instead.
Since your device doesn't need too much current (though it doesn't have a datasheet, which is a big red flag in my book), the TC1014-3.3 would probably be my choice. It's cheap, in a SOT-23-5 package that's a good compromise between small and easy-to-solder, and it has a nice low quiescent current.
If you absolutely must use a through-hole part, (which I repeat that I do not recommend), an LP2950-3.3 or the massively-overkill LM1117T-3.3 should suit your needs.
For any of these, don't forget that they'll need an output capacitor. I'd just go with cheap ceramic ones, but you can use electrolytics if they need high capacitance and you can find one that has a suitably low ESR. I didn't bother checking the datasheets of the ones I recommended, but almost all linear regulators recommend at least one input capacitor and one output capacitor, and most require the output capacitor. These are usually around the 1μF range, so nothing too extreme.