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CC2340R5: CC2340

Munesh Tripathi
Prodigy 140 points

Part Number: CC2340R5

Hi TI team,

I am using CC2340R52E0RGER part in my design and I have few queries please answer on that.

It's having internal crystal oscillator (32.768khz and 48Mhz). So do we require external crystal in any case and if yes than why?

For 32khz crystal, load capacitor are recommended 12pf and 15pf, Is that correct ?

For external 48Mhz crystal oscillator load capacitor suggest do not mount. Is that correct ? and when we have internal 48Mhz cap and its a BLE SOC then why external crystal recommended for radio communication

We operate this device directly by low voltage battery (3V). In that VDDS should be directly connected with battery. what about VDDR ? do we need to provide any voltage on that pin ?

Can we connect VDDR with DCDC pin directly (without any inductor and capacitor)?

what is the use of TVS diode at antenna line ?

We are planning to use F-inverted antenna on top side and it's 4 layer PCB. at bottom side we have some metallic part like switches and battery. Can you provide a path for antenna CAD file. Kindly suggest do's and don't, if any.

Thanks

Munesh Tripathi

  • 0
    TI__Mastermind 21630 points

    Hi Munesh,

    A team member is looking into this and will get back to you as soon as possible.

    Regards.

  • 0 in reply to FI
    TI__Expert 7180 points

    Hi Munesh,

    1. It's having internal crystal oscillator (32.768khz and 48Mhz). So do we require external crystal in any case and if yes than why?

    This depends entirely on the use case. Having both crystals would allow the design to be used as a central hub and peripheral.

    A central hub requires a 32.768KHz crystal and peripheral only requires the 48MHz crystal

    2. For 32khz crystal, load capacitor are recommended 12pf and 15pf, Is that correct?

    Correct, but this may require tuning depending on what types of certifications you are going for, if any.

    3. For external 48Mhz crystal oscillator load capacitor suggest do not mount. Is that correct ? and when we have internal 48Mhz cap and its a BLE SOC then why external crystal recommended for radio communication

    Yes, but it entirely depends on what certification you are going for, which may or may not require tuning. Additionally, the internal crystal is not accurate enough for BLE timing purposes so an external crystal is required.

    4. We operate this device directly by low voltage battery (3V). In that VDDS should be directly connected with battery. what about VDDR ? do we need to provide any voltage on that pin?

    You only need to supply VDDS. VDDR is the output of an internal regulator, which is supplied by VDDS.

    5. Can we connect VDDR with DCDC pin directly (without any inductor and capacitor)?

    We do not recommend this as the inductor and capacitor several purposes such as DCDC ripple filtering. Removing may result in unintended effects as higher DCDC ripple causing more frequent recharges during standby.

    6. what is the use of TVS diode at antenna line?

    This a ESD protection diode which provides a low impedance path for electrostatic discharges to sink into ground protecting the rest of the circuit.

    7. We are planning to use F-inverted antenna on top side and it's 4 layer PCB. at bottom side we have some metallic part like switches and battery. Can you provide a path for antenna CAD file. Kindly suggest do's and don't, if any.

    See our reference design here: https://www.ti.com/lit/zip/swrc381

    Additionally, feel free to submit a design review here and our team will gladly provide feedback: https://www.ti.com/tool/SIMPLELINK-2-4GHZ-DESIGN-REVIEWS

    Best regards,

    Bun