• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 22 subscribers
  • Views 569 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CDC6C: Jitter compared to Crystal

Patrick Ruf
Genius 5095 points

Part Number: CDC6C
Other Parts Discussed in Thread: LMK6C

Tool/software:

Hi,

We plan to substitute some of our crystals with BAW oscillators.
First we planned to use the LMK6CE02500CDLFdevice as it has very good jitter performance and the price is ok.
Now I have seen the CDC6CE025000ADLFR that could also be a good alternative and has far less power consumption.

Can you tell me how the Jitter performance of those devices (especially the CDC6CE025000ADLFR) compared to a crystal oscillator is?
For example when used with a PHY like the DP83822IRHB.

I'm aware of the document snaa362 (Standalone BAW Oscillators Advantages Over Quartz Oscillators) but the CDC6C is not shown in this document.


Thanks and best regards,

Patrick

  • +1
    TI__Genius 17500 points

    Hi Patrick, 

    LMK6CE02500CDLF has better jitter performance compared to CDC6CE025000ADLF (500fs vs.1000fs max RMS jitter, integrated 12kHz-5MHz), but as you noted CDC6C has much less power consumption. From my experience LMK6C and CDC6C have competitive jitter performance compared to other LVCMOS oscillators on the market. 

    For ethernet PHYs specifically, we just released an application note that shows CDC6C meets all clock requirements for 100Mbps Ethernet when paired with the DP83822: https://www.ti.com/lit/an/snaa433/snaa433.pdf 

    Let me know if you have any other questions. 

    Regards, 

    Connor 

  • 0 in reply to Connor Lewis
    Genius 5095 points

    Hi Connor,

    Interesting document. Thanks. That tells me that the CDC6CE025000ADLFR can replace crystals in a variaty of applications up to 100Mbps Ethernet and possibly beyond.

    Any plans to bring out the 20MHz variant (CDC6CE020000ADLFR)?

    Maybe you can tell me the difference between "LMK" and "CDC" in the naming of those devices. Respective what does "LMK"/"CDC" stands for?

    Regards,
    Patrick


  • +1 in reply to Patrick Ruf
    TI__Genius 17500 points

    Hi Patrick, 

    We do have plans to release a 20MHz variant, but no firm timelines right now. Currently our tentative estimate is to release in 3Q or 4Q this year. If you have an assigned sales representative, you can contact them to discuss more about lead times, pricing, project schedules and volumes, etc. This information can help us prioritize the release schedules for new variants. 

    "LMK" and "CDC" don't necessarily stand for anything, but in the past we've used "LMK" naming for our higher performance product families, and "CDC" for our lower power, lower cost solutions. With LMK6C and CDC6C specifically, the main difference is that LMK6C has a fractional output divider (FOD) which can be used to achieve any output frequency between 1MHZ and 400MHz. The FOD is high performance but is not optimized for power consumption. CDC6C uses an integer output divider (IOD) which consumes much less power. 

    Regards, 

    Connor