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LMX2594: OSC INPUT

user5163865
Genius 3980 points
Part Number: LMX2594

Hi,

The customer plans to input a PSEL signal to the OSC INPUT, can it be used with the EVM?

PSEL is Vol=3.2V, Voh=4V, which is a little high, so I made an inquiry.
If TI has a recommended circuit for PSEL input, please let me know.

Another question.
Is RFOUTAP/RFOUTAM an internal circuit like "CML"?

Best regards,
Hiroshi

  • 0
    TI__Guru** 107030 points

    Hi Wada-san,

    I do not familiar with PSEL signal, is it a single-ended or differential signal?

    OSCin input requires AC-couple, so the DC content of the input signal is not important. The voltage swing of PSEL is 0.8V, which is good enough for LMX2594.

    I do not have the exact circuit diagram but I think it is pretty much like the diagram you shown with R1 and R2 being external. 

  • 0 in reply to Noel Fung
    Genius 3980 points

    Hi Noel-san,

    The input configuration is PECL (or LVPECL) instead of PSEL (my typo).

    It doesn't depend on the common mode voltage, so I don't think there is a problem, but just in case, could you tell me again if there is no problem with the EVM circuit?
    P12 of the EVM document only mentioned LVPECL.

    Best regards,

    Hiroshi

  • +1 in reply to user5163865
    TI__Guru** 107030 points

    Hi Wada-san,

    Signal format is not matter, as long as the voltage swing meets LMX2594 requirement, it will work.

    If you going to input the clock signal differentially (connect both OSCinP and OSCinM pins), the voltage swing (Voscin) requirement is 0.1V to 1V.