CC3220MODA: Isolators required Isolate the Neutral

Hi Naveen,

 For the question on if you need isolation that is system level question that I cannot answer. I would recommend you very that you meet the electrical specifications in our datasheet.

To have optimal RF performance I would recommend to follow the guidelines form our CC3x20 SimpleLink Wi-Fi® and Internet of Things Design Checklist (excluding the "BG Band" item) and compare to our example board design CC3220MODx SimpleLink Wi-Fi® and Internet of Things Hardware Design Files.

Please make sure to follow the CC3220MODA layout guidelines mentioned in the datasheet (Lit# SWRS206) and  CC3220MODASx SimpleLink Wi-Fi® and IoT Solution With MCU LaunchPad Hardware User's Guide (Lit# swru512) For example it is important to have the a cutout around the RF Pin and a cutout underneath the antenna (see images below). 

Otherwise there is also a "Three-Phase Electricity Meter Reference Design" TI refence design you can look at https://www.ti.com/tool/TIDM-THREEPHASEMETER-F449 

BR,

Jessica

Hi Jessica,

Thank you for the information.

Please understand our Question. We already using CC3220MOD in our products and working fine. We are extending this MCU in AC power measuring (Energy Meter) Applications. Our question is not related to suggested answers. Kindly advice or please connect with the experts who has experienced in this applications.

Thanks and regards,

Naveen K

Hi Naveen, 

Apologies, but as mentioned isolation between the two is a system level question that I cannot answer. As such I added information on how to mitigate what could affect the RF performance.

You can reach out to the isolation experts by making a new post in the isolation-group forum https://e2e.ti.com/support/isolation-group/isolation/f/isolation-forum .

BR,

Jessica

Hi Jessica,

It is related to MCU/Wi-Fi device and question is very simple on MCU/Wi-Fi safety and Performance prospective.

I have posted the same earlier before posting here, ADS1018 FYI.

Thanks and regards,

Naveen k

Hi Naveen,

No this is not a simple question definitely. Performance of MCU with such connection may or may not be affected. There is many factors which can have effect with such connection. No responsible engineer will give you straight answer. As designer it is your responsibility properly assess risks.

If I were personally design such a device, I will left digital portion fully isolated as safer option. But of course this will be more expensive.

Some inspiration with similar device you can find at this reference design.

Jan

Hi Jan,

Thank you for your advise.

Obviously we designers are the responsible to test and implement for all the design outcomes. We are asking suggestions with manufacturers because they might be tested in most of the applications and their domain expertise knowledge suggestions might be helpful for certain considerations to speedup the development.

For safety Isolation is definitely required. But we need to Test the affects on MCU RF Performance, If these scenario already tested by the manufacturers then we can move in Positive directions or else we need more trials to get it done. 

In the suggested reference design Neutral is connected to MCU GND without Isolation, Hope there is no Performance degradation on MCU here.

Thanks and regards,

Naveen K

Hi Jessica,

Thank you for your information.

Thanks and regards,

Naveen K