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Have I damaged my nRF52832 Dev Kit? [closed]

Rick1997 gravatar image

asked 2017-05-17 15:00:57 +0100

updated 2017-05-19 11:47:18 +0100

I have been analyzing the current consumption of my nRF52832 dev kit today using both a multi meter and an oscilloscope with a resistor. I'm not sure what I exactly did that lead to this, but now my board constantly uses 80mA. It can still be programmed and it does seem to run. Did my board get damaged somehow? If so, can it still be fixed?

Edit: What could have happened is that the dev kit was powered for a short time without a jumper on P22 (also no short on SB9 nor resistor on R6). Not sure what this could do to the board.

Edit2: The issue was temporarily fixed by replace the nRF52832 chip on the dev board but now it's back again. Not sure what I'm doing wrong.

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Closed as "the question is answered, right answer was accepted" by Rick at 2017-06-19 15:13:48 +0100

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1

Hi,

Powering the DK without a jumper on P22 (also no short on SB9 nor resistor on R6) should not have caused any damage. How are you powering the board? What value are you using on the resistor? Could you try different values?

Sigurd ( 2017-05-18 10:54:28 +0100 )editconvert to answer

My colleague helped me replace the chip on the dev board which fixed the issue. We didn't figure out what caused the damage in the first place. I power the board through the P21 header at 3V but also tried using the battery. I used both a 10 and 100 ohm resistor. My only guess what could have happened is that the power supply I'm using spiked above 3.6V for a short moment.

Edit: It just happened again :( Any idea what I'm doing wrong?

Rick ( 2017-05-19 09:24:28 +0100 )editconvert to answer
1

Have you shorted solder bridge SB12? Note that while SB12 is shorted, the dev kit must not be powered from USB if there is a battery or external supply connected because the protection diode has been bypassed. Also note that the allowed voltage level on external supply pins are 1.7 V - 3.6 V.

Sigurd ( 2017-05-19 12:33:48 +0100 )editconvert to answer

Yes I have shorted SB12 and only power it from one source at a time, so either the external power supply or USB while programming. Never both at the same time. One of my colleagues suggested that it could have been damaged due to ESD. Are the dev kits sensitive to ESD?

Rick ( 2017-05-19 13:36:52 +0100 )editconvert to answer
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No, the dev kits are not very sensitive to ESD. Have you shorted SB10 or SB11? Are you measuring on P22? Do you have a resistor on R6?

Is the chip still functional?

If you test with some of the BLE examples in the SDK, is the BLE still working ? are you able to connect to the nRF with a smartphone?

Sigurd ( 2017-05-19 14:43:34 +0100 )editconvert to answer

Neither SB10 or SB11 are shorted. I measure current on P22, sometimes with a multi meter and sometimes with a scope. When using the scope I put a header pin on P22 that has a 10 or 100 ohm resistor between the two pins. That way I don't have to solder/desolder R6 all the time. The chip is functional. Both my own code and the examples work fine and I can connect to it with my phone.

Rick ( 2017-05-19 14:56:36 +0100 )editconvert to answer
1

Could you upload a close up photo of the board?

Sigurd ( 2017-05-19 15:18:51 +0100 )editconvert to answer

Here it is

The area near P22 is a bit dirty but using the continuity function of a multimeter says there is no short.

Rick ( 2017-05-19 15:29:06 +0100 )editconvert to answer

Alright I will remove the bridge from SB12. Is there any harm in using the board like this for a few days to further develop my code (beside current optimization)? My colleague doesn't have time to replace the chip right now.

Rick ( 2017-05-19 16:01:50 +0100 )editconvert to answer
1

I would not recommend it, but it's up to you. Worst case it could potentially damage the voltage regulator used when the device is powered from USB(needed when you program the board), when the nRF is in this state.

Sigurd ( 2017-05-19 16:23:40 +0100 )editconvert to answer

Alright, thanks a lot for all your help.

Rick ( 2017-05-19 16:26:22 +0100 )editconvert to answer

No problem. It could maybe also be an idea not to use that external power supply, and just power it from the USB instead. When powering from the USB it will add some measurement noise, but in most cases this noise is acceptable.

Sigurd ( 2017-05-19 16:53:57 +0100 )editconvert to answer

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sigurdon gravatar image

answered 2017-05-19 15:52:15 +0100

Rick1997 gravatar image

updated 2017-05-19 16:27:06 +0100

The nRF52832 is classified as ESD HBM class 3A(up-to 4000 V), so it’s very unlikely that ESD from human is the cause. My theory is that the external power supply have caused this with voltage spikes. In order for this not to happen again, I would recommend to cut or de-solder the SB12 bridge( in order to activate/reconnect the voltage protection diode again), and then adjust the power supply to accommodate for the ~0.32V voltage drop that is over the protection diode.

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Asked: 2017-05-17 15:00:57 +0100

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Last updated: mai 19