RTOS/CC3220MODA: Weak WiFi Range on CC3220MODA (compared to launchpad)

Hi Zac,

How do you have located your module? Please make sure that there is no ground plating under module antenna. Also you should check if you not have limited TX power on your module by particular API.

Jan

Hi Jan,

There is no ground plating under module antenna and I am using the same firmware on both launchpad as well as the module (hence the TX power would remain same).

The only change I could notice is that the filter caps (2 x 0.1uF) for VBAT1 & VBAT2 got missed in the initial PCB design and is retrofitted by first connecting VBAT1 & VBAT2 together and then adding 2 x 0.1uF caps. Will this have any impact on WiFi range ?

Appreciate your support.

Thanks
Zac

Hi Zac,

Did you explicitly set TX power inside your firmware or you are using configuration from Uniflash. If you not set TX power inside your firmware, then you could have still differently set TX power. Do you use same version of Service Pack?

I am not sure if this missing caps can affect WiFi range. This can be answered by the TI engineer(s).

Jan

Hi Jan,

I am not explicitly setting TX power inside my code and is using Uniflash defaults. Please note that I have flashed the exact same firmware on both CC3220MODA and the lauchpad using OTA and hence do not expect any change in TX configuration or any changes in the Service Packs.

Is there any major change in the antenna design for CC3220MODA compared to the CC3220S-LAUNCHXL ? Can the power supply affect the WiFi range ?

Thanks
Zac

Hi Zac,

Please check by sl_ API how do you have TX power for STA mode.

Yes, antenna design is different (you can check it by yourself). Insufficient power supply can affect wireless performance.

Jan

Hi Jan,

My TX power setting is default (max). For the same OTA firmware, can two modules vary the TX power ?
Regarding antenna design, will CC3220MODA have weaker antennas compared to the lauchpads ? Sorry I am unable to makeout from the design myself.

I am giving sufficient power to the device, however I am not sure how clean the supply is?

Thanks
Zac

Hi Zac,

Information about that both hardware have set same TX power is very important. From this reason we can be sure that there is no issue at software side.

CC3220 chips can have slightly different TX power, but it not look to your case. Antenna gain of CC2200MODA and CC3220S LaunchPad should be very similar (1.9dBi vs 2.5dBi for MOD). From this reason range should be similar. My experiences it confirmed also. Range of signal is comparable regardless hardware is used. I tested this with:
- pre-production CC3220SF LP (rev B.)
- production CC3220SF LP (rev A.)
- production CC3220MODASF LP
- my hardware with CC3220MODASF

I think you should look to your power rail by oscilloscope. Requirements for power supply you find in datasheet. One of important information is that ripple on the supply must be less than ±300 mV (I am not sure if this can cause similar problem as you see).
If you have another hardware you should check with this hardware. Maybe you have wrongly soldered module (wrongly melted solder paste is common manufacturing issue with this modules).
Also you can compare range with CC3220MODASF LP if you have this kit. Maybe you can also post here photo of your hardware, maybe that could be something obvious. Good resource how to design hardware with CC3220SF is LP with this module.

Jan

Hi Jan,

Adding some filter capacitors and moving the module from other components have slightly improved the range, however it is noway near the Lauchpad. I have compared CC3220MODA with LAUNCH-CC3220MODASF (which uses similar antenna of CC3220MODA) and still they shows much difference.

Few questions are
1. TI recommends an antenna overhang of 1mm from PCB edge. I hope this is the minimum overhang and increasing the overhang will not have any adverse effects ?

2. I have some 240VAC (50Hz) lines in the same PCB (sufficiently spaced for isolation). Can this impact my WiFi range ?

Appreciate your support.

Regards
Zac

Hi Zac,

1. I am not 100% but I expect that antenna overhang can be higher.

2. I don't know. Maybe you should try temporarily deactivate this AC part of your board.

Do you have something near module antenna (something from metal, dielectric, etc.). Today I tested antenna performance at CC3220MOD LaunchPad when dielectric material is near to antenna. My LP was inserted into molded case from polycarbonate. MOD antenna was approximately 1.5mm from the case wall. In this test configuration was TX power decreased from -69dBm to -75dBm (that means 1/4 of TX power).

Jan

Thanks Jan,

Can someone from TI answer my question please ?

1. TI recommends an antenna overhang of 1mm from PCB edge. I hope this is the minimum overhang and increasing the overhang will not have any adverse effects ?

2. I have some 240VAC (50Hz) lines in the same PCB (sufficiently spaced for isolation). Can this impact the WiFi range of CC3220MODA?

Thanks
Zac

Hi Zac,

Since the board with the less range is a custom board the issue might be with the layout. Can you share your schematic and layout for review?

1. The placement of the module and RF section affects the RF performance
2. Routing of other traces may affect the RF performance.

Regards,
Charles O

Hi Zac,

We have not heard back from you, so we are assuming that you were able to resolve your issue. If not, please post a reply below or open a new thread if it is locked.

Thanks!
Ben M

Hi Ben,

I am still not able to resolve the issue, however I found that few Vcc lines were running close to the antenna which I have changed and is waiting to be tested (changes would take few weeks).
Can the input supply noise affect the RF performance ?

Thanks
Zac

Hi Charles,

Could you please share your email so that I can share the schematic for review ?

Thanks
Zac

Hi Charles,

I have shared the 3D images for your verification (private message).

Thanks
Zac

Hi Charles,

I have already shared the files with you. Are you able to give a feedback ?
Appreciate your support.

Thanks
Zac