Have I damaged my nRF52832 Dev Kit?

RE: Have I damaged my nRF52832 Dev Kit?

Sigurd — Fri, 19 May 2017 14:53:57 GMT

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.

RE: Have I damaged my nRF52832 Dev Kit?

Rick — Fri, 19 May 2017 14:26:22 GMT

Alright, thanks a lot for all your help.

RE: Have I damaged my nRF52832 Dev Kit?

Sigurd — Fri, 19 May 2017 14:23:40 GMT

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.

RE: Have I damaged my nRF52832 Dev Kit?

Rick — Fri, 19 May 2017 14:01:50 GMT

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.

RE: Have I damaged my nRF52832 Dev Kit?

Sigurd — Fri, 19 May 2017 13:52:15 GMT

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.

RE: Have I damaged my nRF52832 Dev Kit?

Rick — Fri, 19 May 2017 13:29:06 GMT

Here it is

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

RE: Have I damaged my nRF52832 Dev Kit?

Sigurd — Fri, 19 May 2017 13:18:51 GMT

Could you upload a close up photo of the board?

RE: Have I damaged my nRF52832 Dev Kit?

Rick — Fri, 19 May 2017 12:56:36 GMT

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.

RE: Have I damaged my nRF52832 Dev Kit?

Sigurd — Fri, 19 May 2017 12:43:34 GMT

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?

RE: Have I damaged my nRF52832 Dev Kit?

Rick — Fri, 19 May 2017 11:36:52 GMT

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?

RE: Have I damaged my nRF52832 Dev Kit?

Sigurd — Fri, 19 May 2017 10:33:48 GMT

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.

RE: Have I damaged my nRF52832 Dev Kit?

Rick — Fri, 19 May 2017 07:24:28 GMT

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?

RE: Have I damaged my nRF52832 Dev Kit?

Sigurd — Thu, 18 May 2017 08:54:28 GMT

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?