How much current can a 3v3 pin supply on an Arduino Nano clone (ch340)?

Other Hardware General Electronics
1

Hi,
I'm a newbie. For my Arduino Nano clone (ch340) project, I'm trying to connect temperature and humidity sensors and a display with a keyboard that have 3.3V power. Their total load is about 65 mA and I expect to power them from the 3v3 pin. Is it possible to make this work properly?
Thank you! Your advice is important to me.

1 Like
2

  • The best way to answer this is, since 65mA is so low that if the Nano could not supply this, the board is total crap.

  • Confident you will be just fine at taking 65mA from your 3V3 pin.

3

Thanks for your answer! No, I'm not sure, that's why I asked the question. :slightly_smiling_face:

4
  • I am “Confident you will be just fine at taking 65mA from your 3V3 pin”.
5

Thank you! I hope. :slightly_smiling_face:

6

Why not add an external 3.3V regulator with a maximum you do know?

For example MCP1700-33, HT7333

7

Thank you! I wanted it directly from Nana. :slightly_smiling_face:

8

Actually, no, not from a Nano - CH340. On that board the 3.3V supply is provided by the CH340, and the current limit is something like 30mA. The CH340 datasheets I've seen don't spec that, but I think 30mA is commonly accepted. But you can test that yourself with various resistors from the 3.3V pin to ground, and see when the output voltage starts to sag. A 100-ohm resistor would draw 33mA. See how much the voltage sags with that. But in general, I don't think 65mA is in the cards. You would need an Uno for that, which has its own 3.3V regulator.

2 Likes
9

Thanks for your answer! I read that 50 mA is possible. I have a new version 3. I thought they increased it. :slightly_smiling_face:

10

No 65mA is way too much!

11
  • That would be correct if the CH340 is supplying the 3V3 :woozy_face:
1 Like
12

Thanks for your answer. I understand.

13

So how will you get the 3.3V you need?

14

Yes? Only external power supply or is there another way?

15

FYI, the two most significant numbers for any Arduino board is the current capacity of the voltage regulator (~400mA) and the current capacity of an I/O pin (20mA).

16

Thank you!

17

Not to difficult to build a 3.3V regulator. You just need a 3 pin regulator and two capacitors.
If you don't want to build, this is your best bet

1 Like
18

Thank you! This is a good option. I will definitely use it. :slightly_smiling_face:

1 Like
19

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.