How much current can be drawn from pin2/4 of 40 pin header


To make a custom board on 40pin header, I tested drawing
20 mA from pin 2/4 of J12, 40 pin header. I connected 220 ohm
between pin 2/4 and 6 and measured the voltage between
those two pins. It was around 2 V, not 5 V. How can I use
5V pins of J12 correctly?

Thanks in advance for any suggestions.

Please read this doc first:

There are some requests on the drive strength of pins as level shift exists.

Thank you for reply.

I mentioned about power pins, not signal pins. I have both Nano
and Xavier NX. Nano 5V power pin (2/4 pin) can be drawn more
than 20 mA, but 5V power pins of NX cannot supply enough current.
3.3V power pins of NX are OK.

The 5V power of it can be up to 1A supply. How many boards do you have and test? There is a “reverse current block” design as you can see in the schematic, you can measure the vdd_5v_sys to and vdd_5v_gpio on Q23 to make sure which one fails. The schematic and pcb file are here:

I tested Q23. When 200 ohm is connected between pin 4 (5 V pwr) and pin 6 (GND), Q23 drain is 5.11 V, source is 1.99 V and gate is 0.00 V.
Is this data enough?

How many board did you test? Also can you try other pull-down too, such as 4.7k, 50k or others?

I only have one NX.
Now I test 1 kohm, source and pin 4 are both is 3.84 V.
When 47 kohm, source and pin 4 are both 5.07 V.

This means, the internal resistance of power supply is around 300 ohm?

The Drain side is always 5V, right? If so, it is not power supply problem.

Yes, drain is always 5.11 V. The MOSFET looks like a resister.

To check status of mosfet, can you try removing Q24 and using 1k pull-down instead of 47k(R180)?

Also could you send a picture of the rework so as to check how 220ohm was soldered? As it is very strange. Q23 is a P-FET so if its gate is at 0V and drain is 5.11V, then source should be also at 5.11V and not 1.99V.

I can’t rework Q23. Q24 because it is too close to the connector J12.
I don’t solder 220 ohm, only connect a resister between pin 2 and pin 6 of J12 using jump wires.

Can you share a picture of your setting of resistor?

This picture is enough for you?

Thanks, we are checking internally, will update once available.

I borrow another Jetson Xavier NX from my colleague.
It works fine. It can draw more than 100 mA from pin 2 of J12.
It seems my board have some problem.

OK, it looks like the mosfet issue, you can try removing it to validate.

Hello, Does the attached document regarding the 40pin header apply to the xavier nx dev kit carrier board as well (level shifting, ect.)

Yes, the 40-pin expansion header is same.