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User16438042334827474767
Associate II
July 17, 2024
Solved

Internal 48MHZ RC Enough for Radio Application?

  • July 17, 2024
  • 6 replies
  • 1770 views

I am designing an Outdoor Radio product with STM32WLE5CBU6. my question is whether the Internal RC Oscillator is enough for my radio applications ? or do I need to add External TCXO in my circuit considering the outdoor temperature environment? for my product cost-cutting. please suggest.

Best answer by TDK

It needs an external crystal to have wireless transmission capability.

TDK_0-1721221164225.png

 

6 replies

Andrew Neil
Andrew Neil
Super User
July 17, 2024
@User16438042334827474767 wrote:

my question is whether the Internal RC Oscillator is enough for my radio applications ? 

Impossible to say without details of what these "radio applications" are.

You can find the specifications of the Internal RC Oscillator in the datasheet - work out from there whether that meets your requirements.

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
AScha.3
AScha.3
Super User
July 17, 2024

No.

Usually you want/need for GHz or many-MHz PLL a very stable clock source, typical a crystal.

See basic:

AScha3_0-1721213542878.png

HSE32 is the "standard" clock for the PLL. (If 20 ct for a crystal is too much, you have another problem...)

"If you feel a post has answered your question, please click ""Accept as Solution""."
U
User16438042334827474767Author
Associate II
July 17, 2024

Application LORA 868MHZ P2P Weather station.not LORAWAN.

Andrew Neil
Andrew Neil
Super User
July 17, 2024

Again, look at the specs in the datasheet - do they fit with your application requirements?

Local regulations will put requirements on frequency stability/accuracy ...

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
    TDK
    TDKBest answer
    Super User
    July 17, 2024

    It needs an external crystal to have wireless transmission capability.

    TDK_0-1721221164225.png

     

    "If you feel a post has answered your question, please click ""Accept as Solution""."
      Andrew Neil
      Andrew Neil
      Super User
      July 17, 2024
      @User16438042334827474767 wrote:

       for my product cost-cutting. please suggest.

      If you really want to cut costs, do you really need to use LoRa?

      You pay a premium (to Semtech) for that ...

      A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
      U
      User16438042334827474767Author
      Associate II
      July 20, 2024

      Okay. 

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