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Difference CC2531/CC2530

Manuel Menchaca
Expert 2035 points
Other Parts Discussed in Thread: CC2531, CC2530

I was developing a custom board based on CC2531 without USB (USB_P, USB_N, DVDD_USB and DGND_USB Pins unconnected) but for some reason we have to change the CC2531 to CC2530.


Do I have to change the design? What will happen with these pins?

Best regards,

Manuel

  • 0
    Guru 735695 points

    Pin 1,2,3, and 4 on CC2531 are for USB and they are ground on CC2530. I think you need to ground these pins for CC2530.

  • 0 in reply to YiKai Chen
    TI__Genius 16570 points

    Hi,

    yes Yikai is right. Please refer to the Application Information section of the CC2530 datasheet: http://www.ti.com/lit/ds/symlink/cc2530.pdf

    As you can see, pins 1, 2, 3 and 4 must be connected to GND.

    Thanks,

    TheDarkSide

  • 0 in reply to TheDarkSide
    Expert 2035 points

    Hi,

    Thank you for answering so quickly!

    Best regards

  • 0 in reply to TheDarkSide
    Prodigy 230 points
    I'm looking for a better answer than this, preferably from a TI engineer who knows about the chip internals. I have a PCB that uses the CC2531, but we're also offering a non-usb version, so we could use the CC2530. We've tested populating the PCB with a 2530 and it works, even though pin 4 on the 2531 is VDD and on the 2530 is GND.

    In the 2530 datasheet it says on page 17 "The exposed ground pad must be connected to a solid ground plane, as this is the ground connection for the chip." indicating that 1-4 don't NEED to be connected to ground. In addition, on page 18 it says pins 1,2,3,4 are "Unused pins".

    So the question is, what does the 2530 pins 1,2,3,4 connect to internally, and can I get away with connecting those pins to something other than ground?
  • 0 in reply to Bob Baddeley
    Guru 31280 points

    Hi,

    From my own experience pin 1,2,3,4 can be left floating without any impact oncc2530 performance.

    Bob Baddeley said:
    can I get away with connecting those pins to something other

    Like what?

  • 0 in reply to Igor Sherer
    Prodigy 230 points

    Well, I want to populate a board laid out for a 2531 with a 2530 instead. That means 1 goes to ground, 2/3 go through resistors to D+ and D- of USB, and 4 goes to VDD (3.3V). I know 2530 doesn't support USB, and that's completely fine. I just need to make sure that attaching pins 2,3,4 to things that will have voltages of 3.3V on them is ok.

  • 0 in reply to Bob Baddeley
    Guru 31280 points
    I haven't touched the cc2530/1 for a long time now, but I can test it tomorrow (at least try to) and get back to you with an answer.
  • 0 in reply to Igor Sherer
    Prodigy 230 points
    Thanks, Igor. I've already tested and I know that it doesn't explode and actually works just fine. But what I was hoping for was an answer from TI about the internals of the chip and whether it consumes extra power or has other negative effects or something that I wouldn't be able to necessarily directly observe if I hook those four pins up to something besides ground.
  • 0 in reply to Bob Baddeley
    Guru 31280 points

    Hi,

    Well, since cc2530 and cc2531 are SoCs and the only difference between these two devices is the USB functionality, I would go and guess

    that in cc2530 there is nothing on silicon instead of an USB module, thus making it kind of a blind spot with 4 external pins that are not

    internally connected to ground.

    But, let's wait for an answer from TI guys. :)

    Have a nice day.