Boron LTE Resets when setting A3 High

jrgray50 · October 31, 2019, 3:27am

I’ve purchased a number of PR54-7 boards for a customer product. To reduce power consumption I’ve desoldered the J1 jumper to connect the I2C power controller to A3. (Note: the boards I review had the I2C power controller pin soldered to the 3.3.v pad of J1. This is in contrast to the boards documentation). When I enable A3, the Boron LTE resets. I suspect that the A3 pin cannot source enough current to support the I2C power controller.

Does anyone have any insight into this issue? Or, are others seeing the same issue.

Thanks in advance for the help.

Bhaskar · October 31, 2019, 2:09pm

Hi,
The IO controls a FET and FET controls the Power supply.
Try setting the A3 high manually and see if it still resets boron.

are you using the battery or usb to power the boron ?

Thanks

rfontaine · October 31, 2019, 5:45pm

The boards that I’ve purchased were soldered as per the Docs :

Note: It’s my understanding that this is (3) pads.
Default is the Top (2) connected, which allows 5V Boost control via Pin A3.
The other option is all (3) pads connected, not just the bottom (2).
(You mentioned that you de-soldered)

How are your Pads connected now?
Which firmware version are you using on your Boron?

jrgray50 · October 31, 2019, 6:02pm

Thanks for the response Bhaskar,

I’m powering the Boron LTE via battery.
I’ll try running via USB to see if there is a difference.

jbesselm · February 12, 2020, 5:52am

jrgray50, I’m seeing the same behavior. The three PR54-7 boards I purchased also came to J1. When I set A3 HIGH the Boron LTE resets. This behavior seems unique to the Boron. The board works fine with an Argon. Did you come up with a solution?

jbesselm · February 12, 2020, 4:13pm

For anyone else that runs into this issue, I was able to solve it by adding some capacitance to the 3v3 pin of the Boron. I suspect that when A3 is set high, presumably switching the 3.3 to 5V boost converter, on there is a current inrush that momentarily drops the 3v3 or Vin below that required. With a 470uF capacitor placed on 3v3 to ground the board works as expected. Also the 3 units I received had the J1 to center pad soldered, not center pad to A3 as described in the documentation.