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LMK04832-SP: required VCXO specification

David Park
Expert 6980 points

Part Number: LMK04832-SP

Hi,

Could you provide the guidance on PLL unlock issue with specific VCXO?

the issue is as below.

  • no issue(CPout 1.4V~2.3V swing) with 603281 from Crystek
  • PLL unlock issue(CPout 3.2V continous output) with MCM8730 from Q-tech

603281 output is 0~3.3V and MCM8730 output is 0.5V~6V.

Please guide what customer set for this issue.

 

Thanks.

 

  • 0
    TI__Guru** 114760 points

    Hi David,

    I cannot find the datasheet of MCM8730. If this device requires a tuning voltage of 3V to get the correct frequency, then you have to use active filter for PLL1. 

    Usually, VCXO requires Vcc/2 as the tuning voltage for the specified frequency. So for a 3.3V VCXO, the tuning voltage is around 1.65V.