XIAO nRF52840 - Maximum current output of 3.3v output

[Jordy_K]

Hi,

I just can’t find a clear answer to the question:
What is the maximum current that can be drawn from the 3.3v output on the XIAO nRF52840?

The latest info I could find is in the links below.

So if the XIAO has an SGM2040, the maximum current on the 3.3v output would be 250mA right?

But it is also mentioned that the selection of the voltage regulator depends on the market supply when the boards are produced.

I bought the XIAO about a year ago, but how can I be sure which regulator is on my boards and how much current I can draw from it?

Thanks.

Where can I find the Part Number for the LDO on XIAO nRF52840?

Hi, I’ve checked all available documentation for the XIAO nRF52840 / Sense boards and the part number for the LDO regulator is nowhere to be seen. Even in the schematic, it’s just labeled U6. I need to know the part number in order to check with the datasheet and ensure I select optimal VBAT parameters. I’d rather not take off the shielding off my boards just to find out a chip P/N. Does anyone know what part number the LDO regulator on these boards is? Thank you in advance! Cheers

SGM2040 data sheet and product information - SGMICRO

[PJ_Glasso]

Hi there,

So the device max is 200ma. @ 3.3v so The pins are 25ma.
The regulator is good for 100ma. (model) I use 20ma. no problem However I wouldn’t exceed 40ma.
and use a heatsink on the bottom thermal pad.
YMMV

GL PJ

[Jordy_K]

Ok, thanks.

So the maximum total power consumption is 200mA for the board plus everything connected to it? But do you say that the max current output on the 3.3v output is 100mA?

The thing is, I want to power an M5Stamp SIM7080 from the 3.3v output. Without the SIM7080 the total power consumption is max 5mA.

The SIM7080’s (very short) peak current draw is 150mA @ 3.3v and goes down to ~50mA.

So by your answer, this is not possible?

Thanks

[PJ_Glasso]

Hi there,

I don’t think it will work. Those 7080 take more, 150ma. is on the low end. You need a big battery if so.
the 150ma. was the max all GPIO sinking current. It won’t last long forsure.
HTH
GL PJ

[cgwaltney]

are you just talking about directly out the 3v3 pin… the power comes into the USB cable at 5v goes thru the internal regulator and comes out as 3v3 on that pin… it also supplies the operating power for the rest of the device… I would assume the maximum power you could sink thru that pin would be limited to the lesser of the maximum 5V input power over USB and the maximum power of the onboard regulator

[Jordy_K]

@ cgwaltney Thanks and yes, I think that would indeed be the answer to my question if I knew which regulator is on the XIAO

I downloaded the Kicad schematic for version 1.1 and the regulator is a TLV733P (see below). My board doesn’t have a version nr on it so I’ll assume it’s v1.0 with an SGM2040 on it.

Link: https://files.seeedstudio.com/wiki/XIAO-BLE/SeeedStudio_XIAO_nRF52840_v1.1_SCH&PCB.zip