• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 78 subscribers
  • Views 244 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MSP430 product selection: MCU with integrated crystal capacitors

Justus Rijke
Prodigy 40 points
Other Parts Discussed in Thread: MSP430G2553, MSP430FR2311

Hi,

In our products we use the MSP430G2553. This MCU has integrated capacitors to drive a crystal.

We're in the middle of selecting a new MCU in the FR range, with integrated caps. But I haven't found a filter in the MSP430 product selector tool (https://www.ti.com/microcontrollers-mcus-processors/msp430-microcontrollers/products.html) specifically for these integrated capacitors.

Is there any way to get a list of MCUs with integrated caps?

Thanks,

Best regards,

Justus

  • 0
    TI__Mastermind 28426 points

    Hi Justus,

    Integrated caps for external crystal?

    New device for MSP430, we don't have this components because this cap need match with external crystal spec.

    Why you need intenal cap, I think just two cap for this circuit.

    Thanks!

    Best Regards

    Johnson

  • 0 in reply to Johnson He
    Prodigy 40 points

    Hi Johnson,

    It saves a bit of board space and reduces layout complexity. The caps are configurable (i.e., easy to match with the crystal' specs):

  • 0
    Prodigy 40 points

    A bit more background on this request. We have a PCB with a MSP430FR2311. On approx. 10% of the PCBs we order we notice that the crystal startup time is several seconds. This is something we haven't had with the PCBs with MSP430G2553 (where we use the builtin caps), so we'd like to use that PCB layout but with a different MCU (as we already have to redesign that PCB for other reasons).

    However, we assume this issue is related to the PCB layout and/or wrong capacitor selection. A PCB layout review might be out of scope for the TI forum, but maybe somebody notices something wrong...

    Schematic:

    Crystal: Epson Q13FC1350000400 (same as used in some TI development boards), 12.5pF
    Caps: Yageo CC0402JRNPO9BN220

    Layout:

    Thanks,

    J.

    *Update* this question has been posted on StackExchange. The original open question remain unanswered though: where to find a list of MSP430's with integrated/configurable caps for XT1.

  • 0 in reply to Justus Rijke
    TI__Mastermind 28426 points

    Hi Justus,

    I am not soue if this document can help you:

    https://www.ti.com/lit/an/slaa322d/slaa322d.pdf

    I think 22pF should OK for this crystal.

    And I also checked MSP430FR2311 datasheet, the typical value for startup time is 1000ms:

    Have you try to did some A-B-A test to check if this issue follow MSP430 or crystal?

    Thanks!

    Best Regards

    Johnson

**Attention** This is a public forum