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Jitter cleaner for square wave

Koki Tsushima
Intellectual 975 points

Other Parts Discussed in Thread: TAS5825M, LMK04208, CDCM6208V2G, LMK5C33216

I am Koki Tsushima who is NCG FAA.

I currently search jitter cleaner for Audio amp such as TAS5825m.

I want to search jitter cleaner for square wave because TAS5825m activates for that one.

But I do not chose how to select of output type of jitter cleaner for square wave.

And also I want to know the input type, too for BCLK.

  • 0
    TI__Intellectual 975 points

    I should have stated in detail.

    Our account seeks for a jitter cleaner for…

    ・Inputting Audio amp such as TAS5825m for PE.

       -Voltage is 1.8/3.3V (1.8V may be difficult for jitter cleaner, but 3.3V may be less problems for jitter cleaner )

       -SCLK: 12.28MHz for I2S and 24.57MHz for TDM at max, and the minimum frequency is 1.024MHz.

                    This may not be problem.

                    (MCLK is not need for TAS5825m, so I focus on that SCLK, instead.)

    ・Controlled by hardware.

       -I cannot find the device which meets this.

    ・Available samples soon.

    The jitter cleaner which meets some of requirements is like lmk04208.

    This device meets SCLK requirements when LVCMOS CLOCK OUTPUTS mode is activated

     (Note that differential output is NOT acceptable for input of TAS5825m).  

    However, customer wants to control by inputting pins (or hardware), not by software .

    I can not find the jitter cleaner which meets all of them.

    Do you recommend some devices?

    Koki

  • 0 in reply to Koki Tsushima
    TI__Genius 16350 points

    Hello Koki,

    Please keep in mind that jitter requirements were not stated but I took a comparison to LMK04208 - Approx 150 fs, RMS is there a more exact number?

    Additional requirements are 2 different outputs 12.28MHz and 24.57MHz utilizing LVCMOS output type and hardware controlled, alternate EEPROM images could be a solution with a pin to switch images.

    Are there other requirements I am missing?

  • 0 in reply to Aaron Black
    TI__Intellectual 975 points

    Yes, that requirements are correct.

    Hopefully, if there are jitter cleaner which can be activated 1.8V is better, but I think these devices are just a few and all of them are not require the output type. Therefore 3.3V driven device is needed.

    I think these are just technical needs and there were no comments for the charectactristis of jitter cleaner.

    And this will be used for audio, then the rating is catalog and hopefully available sample soon.

  • +1 in reply to Koki Tsushima
    TI__Mastermind 34770 points

    Tsushima-san,

    TI has very few pin-controlled PLLs to begin with. There are a few very old audio clock generators (https://www.ti.com/audio-ic/specialty/clocks/products.html) but I doubt any of them meet the customer's jitter requirements. Likewise, we have some pin-programmable PLLs such as CDCM6208V2G, but they are older devices with lower performance and many include a SPI bus for settings not covered in pin modes. Unless one of these meets their needs, I doubt we have something satisfactory.

    In theory, they could also use a network synchronizer with a DPLL as a jitter cleaner, in which case the LMK5C33216 configured to use only DPLL3/APLL3 would meet their requirements (by using EEPROM to pre-configure the device operational state). I doubt this is what the customer wants to use.

    In practice, something like LMK04208 with a $0.30 MSP430 could be used, with the MSP430 acting as a "programmable" external EEPROM: by loading the register configuration for the LMK04208 into the MSP430 nonvolatile memory, the MSP430 could be made to emit the appropriate SPI programming for the LMK04208 on POR or pin-toggle, with very little software effort.

    Since we have no other suggestions, I'll mark this question as "TI Thinks Resolved" for now. If the requirements change, or of you have other questions, please feel free to continue the thread.

    Regards,

    Derek Payne