Hi,
I looked for this in Google but nobody looks like having a consensus. Would it be safe to power nrf24l01+ PA LNA (high power version) using the 3.3 V pin from arduino? The datasheet says it will draw no more thn 140mA and I think this wouldnt damage the 3.3 V pin, correct?
That would depend on which Arduino you are talking about. You can actually find this info on your own. Look at the schematics for your arduino, find out what regulator it uses for 3.3V, then look up the datasheet.
and I think this wouldnt damage the 3.3 V pin, correct?
No wrong for most Arduino's. The original one had a limit of 60mA.
An Arduino Uno/Mega can only supply 50mA from it's 3V3 source. Not enough for a nRF24L01 module with pa LNA. I have played with lots of nRF2401 modules, they need a very stable power supply to work reliably. I mostly power them from a seperate 3V3 regulator.
"An Arduino Uno/Mega can only supply 50mA from it's 3V3 source."
That was true when FT232 was the 3.3V source. Cards since ~ 2010 use a 3.3V regulator instead that can supply 150mA.
Most find that adding a 10uF electrolytic cap to the 3.3V line is needed to support nrf24L01 current surges.
https://www.arduino.cc/en/Main/ArduinoBoardUno says DC Current for 3.3V Pin 50 mA, Arduino Mega page says the same. I know they both use a small linear 3V3 regulator, didn't know it was rated for 150mA.
Honsestly I cant find the 3.3V voltage regulator of my board. It only has the 5v regulator, so where is it? If I could find the 3.3v voltage regulator I could surely check the datasheet of it. This is where I bought my arduino > http://produto.mercadolivre.com.br/MLB-734097309-arduino-nano-v30-cabo-1m-_JM
Oh, a Nano - Arduino Nano's don't have a 3.3V regulator, it comes the FTDI chip, 50mA. I don't know if that is enough for nrf24L01 module. Try adding 10uF cap, see if that helps.
Schematic
Yes, it's a Nano. I took a look at my UNO and I think it also does not have a voltage regulator to 3.3v. This is it: http://produto.mercadolivre.com.br/MLB-708759787-arduino-uno-r3-smd-atmega-328p-pinos-pronta-entrega-_JM
I can only find one voltage regulator in it, where is the other? That one is surelly the 5v.
batata004:
Yes, it's a Nano. I took a look at my UNO and I think it also does not have a voltage regulator to 3.3v. This is it: http://produto.mercadolivre.com.br/MLB-708759787-arduino-uno-r3-smd-atmega-328p-pinos-pronta-entrega-_JMI can only find one voltage regulator in it, where is the other? That one is surelly the 5v.
The board you are linking to is NOT an Arduino Uno, but some Chinese clone. You will need to ask the seller for the exact details.
@Bajdi I already did know that.