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CC1310 MCU GND pad and reference design

Julia Faerber
Intellectual 405 points
Other Parts Discussed in Thread: CC1310

Hello TI support.

I am currently designing a very very small PCB circuit with the CC1310. I have 3 questions.

1: Is the pad underneath the CC1310 5x5 (RHB package) an exposed GND pad or a thermal pad?

2: If I follow the CC1310 and the Launchpad reference design I can see the a lot of inductors and capacitors  are connected just before the antenna. I have attached the design. Is that a balun and a filter? And can I exchange both for my own small matching circuit? I am struggling with space on the PCB, otherwise I would keep it all as it is. The frequency I will be using is 433MHz.

3: How do I find out the values of the VDDS/VDDR decoupling capacitors for my circuit? Can I just keep the ones from the Launchpad reference design?

I am looking forward to your reply.

Cheers

Julia

  • 0
    Guru 12956 points
    TI should answer some (especially #2) but my understanding-

    1. Yes, it's the only GND connection in the package in fact and it dissipates heat too. The RGZ and RHB packages have the center pad as their only GND, it's the RSM package (4x4) that has Vss broken out to some perimeter pins.

    2. Balun and filter, yes.

    3. The decoupling appears to be 100nF (0.1uF) all around which is a common value for a lot of applications I've found. VDDR has a bulk power capacitor too (22uF listed in this sheet, I've used 10uF but I'm not 100% sure if I'm giving up anything by doing that).
  • 0 in reply to Eric Brundick
    TI__Guru**** 317180 points
    1) Since it's ground it's important to use as many vias as possible, ref the reference design.
    2) You should follow the ref design with the regards to the balun and filter but you can consider trying to use 0201 components to save space.
    3) Follow the ref design
  • 0 in reply to TER
    Intellectual 405 points

    Thank you two for answers. It's more clear now. 2010 components are unfortunately too small for our workshop to solder on :(

    I need just one more clarification: -->3)  As I am using the 5x5 version of the CC1310, but I follow the 7x7 launchpad reference design is there a difference in the coupling capacitors? Or can I just stick to the 100nF as Eric mentioned?

    Many thanks for your help.

    Julia

  • 0 in reply to Julia Faerber
    TI__Guru**** 317180 points
    We have reference designs for 4x4, 5x5 and 7x7
  • 0 in reply to TER
    Intellectual 405 points
    Yes, now I got it. I compared a reference design which I downloaded from one of the other blog entries (CC13xxEM-7XD-4251 ) which shows the 433Mhz launchpad version. I thought it used the 5x5 version, but I misread it. Sorry for the last question.
    That's it for now and thanks for the help again.
    Julia