Notecard high current consumption

Hardware
1

Hi,

I have a notecard that is consuming about 4.9 mA at idle from pins VMODEM_P.

SKU: NOTE-NBGL500, fw: 1.5.5.13080.

Everything seems to work properly.

I did {“req”: “card.restore”,“delete”:false,“connected”:false} without success.

Thanks

2

Hi @Alec,

There are some steps you can take to debug this issue:

As a one-time test, ensure that the modem doesn’t power on at all after issuing {"req":"hub.set","mode":"off"}.

Make sure nothing is plugged into VUSB.

Check that AUX_EN is either “open” or pulled low. Also make sure you are not pulling any of these pins low in your design: ATTN, SDA, SCL, RX, TX, VIO.

Finally, make sure that neither of the VACT_GPS pins is inadvertently grounded.

3

Hi,

No change on the current consumption.

I installed the notecard on a notecarrier to configure the modem off and check if the mode stayed off after powered off.

I did the test with a basic connection board having a M.2 connector with all pins exposed. Nothing is connected except for the ground, and both powers.

The current on the VMODEM_P pins is still 4.9mA. If I disconnect the power on the VIO_P pins, the current goes down to 400uA.

I did the same with a new notecard not used yet. The current on the VMODEM_P pins is less than 1uA (about 700nA) having the VIO_P pins powered or not.

Thanks.

4

Hi Alec,

I’m going to try to repro this issue using an NBGL-500 and Notecarrier-B.

While I’m working on that, can you confirm the voltage you are supplying to VIO_P. VMODEM_P doesn’t function properly without VIO_P always being supplied to power the STM32.

Thanks,
Zak

5

Hi,

The VIO_P voltage is 3.3V.
The VMODEM_P voltage is 3.8V.

6

Hi Alec,

I was unable to reproduce your observation.

Here are the steps I used:

  1. {“req”: “card.restore”,“delete”:false,“connected”:false}
  2. {"req":"hub.set","mode":"off"}

I used a NOTE-NBGL500 with firmware versions 1.5.2.12200 and 1.5.5.13080, and I did not observe current consumption in the mA range.

Can you provide me with better repro-steps, or share a schematic of your hardware?

Thanks,
Zak

7

Hi,

As I wrote previously, I cannot reproduce this behavior with another notecard. I guess the problem is for this specific notecard. However I’m still able to use the notecard. There is no visible symptom of the problem while using it.

The hardware used is a basic PCB with a M.2 connector having each pin connected to a 100mil header pin.

Thanks