IWR6843ISK: Heat sinking between antenna module and mmWaveICBoost carrier

Hello,

for sure I double checked the PCBs around those holes for screws and to avoid any shorting I placed a plastic washer on the right side of the mmWaveICBoost. On the left side the heat sink was wide enough. Firstly I tested the kit in a stand-alone mode using a mm-wave demo which went well. Then I connected the DCA1000, configured the mmWaveICBoost and perfromed a few raw data acquisitions in mm-Wave Studio v.2 successfully. The FDTI on the mmWaveICBoost was disconnected from an USB port on a PC in the picture given above. On the next day I started to configure the kit from mm-Wave Studio again and during the firmware download the procedure got frozen. I restarted the kit and mm-Wave Studio all over again but the XDS debugger / COM port disappeared from Device Manager. The LED "PGood" on the antenna module went off, and all further manipulations did not help recover the module. I also noticed that the area around the radar chip became very hot. I switched the kit off, removed the screws between the module and carrier, and tried to start a mm-wave demo but Uniflash couldn't detect the radar anymore. By the way the antenna module without those heat conducting screws was decently cold when the power was on, "PGood" was off. Certainly I took care of SOP jumpers and switches while working with the kit in different modes.Any idea what went wrong?

Thanks,

Timofey       

Hi,

• Does the XDS110 interface come back up when you place a different antenna board on the MMWAVEICBOOST?
• What duty cycle were you running on and for how long?
• What is the voltage and current ratings of the power supply used 
• Have you tried troubleshooting the antenna board? Are the voltage output on the PMIC voltage rails, supply input and and voltage nodes on the device expected level?

Regards,

Charles O

Hello Charles,

herewith my point-to-point answers:

1) yes, the XDS110 comes back with a new antenna module.

2) not greater than 22%, I was running a DataCaptureDemo_xWR.lua with its own settings. In fact the demo crashed during the firmware download.

3) 5V / 2.5A.

4) we found out that PMIC 1V24 is not OK (low) which means no supply to LDO at U5 for PGood. More specifically, the voltages were measured as follows 

TP2  0.0V faulty

TP3  0.8V faulty

TP4  0.68V faulty

TP5  0.59V faulty

TP6  0.68V faulty

TP7  0.68V  faulty

C45  3.3V  OK

C40  1.8V  OK       (PMIC1V8)

C47  0.0V  faulty   (PMIC1V24)

C5    1.8V  OK

C18  0.02V  faulty

C22  0.02V  faulty

C26  0.0V  faulty

Hope this helps. 

BR

Tim

OK, thanks!

Then I will connect the heat sinks on the left side only where metallization is pretty wide on both boards.

No screenshot, sorry, no wish to replicate the damage... It's easy to imagine frozen progress bars in mmWave Studio and Uniflash.

BR

Tim 

Hello,

understood. I replicated the experiment with a good antenna module carefully. When I connect the evalkit in mmWaveStudio and run the data capture demo for the first time, then everything goes smoothly and the demo after a while returns a Matlab figure with signals. But when I run the demo once again in the same environment it gets frozen during the MSS download. At this point the problem began with the damaged antenna module as I recall... Now I turned off the evalkit, terminated mmWave Studio from Task Manager, restarted everything and ran the demo smoothly again but only one time. See screenshots below. By the way note a duty cycle of 51,2% now, my previous estimate of 22% was based on one Tx and 0 idle time. 

Looking forward to your conclusion. 

BR

Tim