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CC3235MODS: Gasket just for Pick and Place or has it electrical function?

Part Number: CC3235MODS
Other Parts Discussed in Thread: CC3235S,

Dear all

Comparing the CC3235MODS and CC3235S there are extra peripheral components on the MOD. Since both are Wi-Fi cetrified, I though, that maybe the gasket was just added to the MOD for ease in pick and place in the production line.

Is that correct or does the gasket serve some electrical / RF purpose too?

Many thanks for your reply

Chris

  • Hi Chris,

    Could you specify which peripheral components you are referring to? The Module (CC3235MODS) will have many peripherals and components inside including the IC (CC3235S). The CC3235S is referred to just be the IC, and you will need to add components on your design like the RF switch and diplexer. 

    If you mean the metal shield on the module, it helps provide a bit more RF shielding from the device and components inside.

    BR,

    Jessica M. Torres 

  • Hi Jessica

    I was refering to what ever is under the hood (gasket) on the CC3235MODS except for the CC3235S (which I regard as the core of the module).

    Ok, the Gasket does provide EMI shielding. Is it possible to build an application without the Gasket and still get certified without problems?

    Kind regards

    Chris

  • Hi Chris,

    I will look into it and get back to you.

  • Hi Jessica

    Are there any news regarding the gasket?

    Kind regards

    Chris

  • Hi Chris,

    Apologies for the delay. If you intend to leverage the certification of our module devices, it is not recommended to remove the metal shield on the Module devices. As explained in section 9.13.2 IC/ISED Certification and Statement of the datasheet :

    The CC3235MODx and CC3235MODAx modules from TI are certified for the FCC as a single-modular transmitter. The modules are FCC-certified radio modules that carries a modular grant. You are cautioned that changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.

    BR,

    Jessica

  • Hi Jessica

    Thank you for your answer. 

    That's funny... I did not intend to remove a gasket from a MOD, I wanted to know if I need to add one, if I use a bare CC3235.

    In other words: what happens to all that people that employ a CC3235 (not the CC3235MOD) on their board? Will they face problems in the certification? And if so, where can they get the gasket to get a robust design comparable to the MOD devices?

    Kind regards

    Christian

  • Hi Christian,

    This depends on how your device is designed and this need to be determined during your hardware deign stage and preliminary EMC testing. It may to be good praxes to design your device to be able use additional sheiling. During your preliminary EMC testing you will determine whether shielding cans are needed or not.

    There is many companies which are producing customised RF shielding cans. Also you can buy some "generic" RF shielding can at shops like Farnell or Mouser.

    From you questions it seems to me that you don't have much experiences with RF design. If you are working at commercial design, it will be good idea ask someone with experiences with RF design. Proper RF design is crucial for good performance of CC32xx devices.

    Jan

  • Hi Jan

    Thank you for your reply.

    My experience is in the 868Mhz band and Bluetooth. However, I never used gaskets so far, unless they come with the module I use.

    I will have TI check the desig (which I basically copy from the Demo). 

    Your point is helpful - it has not occurred to me to take some generic gasket. Probably I was just stuck in my thoughts.

    Thanks a lot

    Chris

  • Hi Chris,

    If you have experience with Bluetooth you should not have problem with WiFi, even 5GHz can be slightly tricky.

    If you don't have concern about space at your PCB and you don't plan high volume production, solution with generic shielding can should be fine for you.

    Jan

  • Hi Chris,

    Apologies for the misunderstanding of the question.  As Jan mentioned the need for shielding depends on your product design, but it is not always necessary to put a "gasket" on the device itself like the CC323xMOD.  The CC3235MOD has a shielding to help with emissions and be a modular product for customers to leverage our certification. The issues you may face for certification depend on your board design.

    I recommend you follow our C3135, CC3235 SimpleLink Wi-Fi® and IoT Solution Layout Guidelines (lit# swru536), and the CC3x35 Hardware Design Checklist  .  You may also request a HW design review at https://www.ti.com/tool/SIMPLELINK-WIFI-DESIGN-REVIEWS

    Thanks for your patience,

    Jessica