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LMK03318: LMK03318 performance and configuration

Elder Costa17
Expert 2825 points
Part Number: LMK03318
Other Parts Discussed in Thread: CDC7005, , CODELOADER, LMK03328

Hello,

I have two questions:

1- How LMK03318 compares with CDC7005 in terms of jitter performance?

2- Is there a tool that allows me to configure it? Or a software library of some sort?

To provide more context on Q.1 above, I need a low jitter clock source. I have a legacy project based on CDC7005 which performance is good. I am working on a new design that has similar requirements but based on more recent components and I am considering LMK03318 because or the LVDS interface support.

Clock requirements are:

Input: whatever works.

Outputs: 2 x 40MHz LVDS, 4 x 5MHz LVCMOS.

About the LVCMOS output, how does it affect jitter, system wise? Does using LVDS and a clock distribution IC provides any advantage?

Thanks in advance.

  • 0
    Expert 2825 points
    Afterthought question: is there a configuration using the GPIO pins that allows me to obtain the outputs above? It is extremely difficult to figure it out from the data sheet.
  • 0 in reply to Elder Costa17
    TI__Genius 16845 points
    Q1. How LMK03318 compares with CDC7005 in terms of jitter performance?
    A1. LMK03318 is lower than CDC7005 under most operating conditions. LMK03318 datasheet table 8.26 shows the maximum jitter to expect under different operating conditions. The CDC7005 jitter depends on the VCXO that is selected. This app note analyzes the jitter performance of CDC7005 when using different VCXOs: www.ti.com/.../scaa067a.pdf.

    Q2. Is there a tool that allows me to configure it? Or a software library of some sort?
    A2. You can use the CodeLoader GUI to program the LMK03318EVM. Download here: www.ti.com/.../CODELOADER

    Q3. About the LVCMOS output, how does it affect jitter, system wise? Does using LVDS and a clock distribution IC provides any advantage?
    A3. LVCMOS clocks will have more jitter than differential clocks. The LVDS format has lower jitter than LVCMOS, but using a buffer will also add some additive jitter to clock outputs. I would make the determination based on your system's jitter requirements and clock format requirements.

    Q4. is there a configuration using the GPIO pins that allows me to obtain the outputs above?
    A4. I checked through the ROM pages and EEPROM pages and there isn't a preloaded configuration to generate your output frequencies. If you would like assistance to generate a config I am happy to help.

    Kind regards,
    Lane
  • 0 in reply to Lane Boyd
    Expert 2825 points

    Hi,  Lane,

    First of  all, thank you very much for your prompt response.

    I will take a look at the  documentation, thank you for the link. Also, thank you for the hint on table 8.26: the amount of information in the data sheet is overwhelming, it is pretty easy to get lost in the middle of it. :-b

    I  do not have the EVM. I tried to run CodeLoader anyway and it crashed with a code violation error. It would be great if it could run off-line (without the EVM) and showed and stored the configuration on a file to be used later.

    I will accept your offer about configuration but first I will make the schematics to determine  which output goes where. I will consider your comments about LVDS vs. LVCMOS jitter.

    Once more, thank you very much for your support.

    Elder.

  • 0 in reply to Lane Boyd
    Expert 2825 points

    About CodeLoader 4 error I mentioned above, the exact error is "Run-time error "6": Overflow" and then it quits. I am using Windows 10 64 bits.

    I installed TICS Pro and it loads and works but has no support to LMK03318. It has support to LMK03328 though. How similar are they other than the second PLL?

  • 0 in reply to Lane Boyd
    Expert 2825 points
    Hi, Lane,

    I have played with TICS Pro (with LMK03328) and I think I figured thinks out. I may have other questions later but for now I may move forward.

    Once again, thank you for your support.

    Elder.