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LM567C: Application Circuit for Frequency Detector (10KHz)

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Replies: 3

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Part Number: LM567C


We are trying to use LM567C for the below application.

I am unable to find the proper working application circuit for this. Could you please suggest the Application Circuit for the Frequency Detection of 10KHz

  • Hello,

    Please refer to the AC test circuit on page 18 (11.2.5).  Equations to calculate center frequency (top of page 9) & bw (bottom of page 10).

    Reviewing this datasheet I also found:

    Pin Functions table shows T_CAP as pin 5. It should be pin 6.
    Pin Functions table shows T_RES as pin 6. It should be pin 5.

    I've put a ticket in for this to be updated in datasheet.



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  • In reply to Timothy T:

    Hi Timothy,

    Thanks for your reply. We tried using the circuit you mentioned.(AC test circuit on page 18 (11.2.5)). 

    and we calculated values for center frequency 10 KHz & bw 14% of f0 with circuit below:

    When we gave Input around bandwidth of 10 KHz, the ouput we were getting is around 20 KHz but what we expected is continuous low. Other than the bandwidth frequency, we were getting continuous high as expected.

    Is it Acting like Frequency Double circuit? or could you suggest any changes in the circuit?


    Arun Prasath

  • In reply to ARUN PRASATH:

    Hi Arun,

    I just built one myself recently. Please see if you can replicate my results and maybe you can start from there.

    LM567C bench report.pdf