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LMK1D1208: LMK1D1208RHDT

Patrice Ducharme
Prodigy 10 points
Part Number: LMK1D1208
Other Parts Discussed in Thread: LMK00334, LMX2594

Hi,

I have a multi-channel sine waveform source; each channel can be configured as differential or single end or differential with AC coupling.


With that sine source, can i feed inputs of LMK1D1208RHDT, LMK00334RTVRQ1, LMX2594RHAT to get quality square wave output clocks ?

i need to know for each of the above 3 TI product:

-which inputs i should route to (prefered for best performance, lowest jitter) ?
-should i use differential or single ended, or should i used differential with AC coupling for my sine source channel config ?
-Voltage programming (Vdiff, Vcom, etc) for sine source i should use = ? (for best performance)


-Application:
-LMK1D1208: Sine source channel1 to feed 133Mhz at inputs of the LMK1D1208; LMK1208 would output a 133Mhz differential square waveforms.
-LMK00334: Sine source channel2 to feed 100Mhz at inputs of the LMK00334; LMK00334 would output a 100Mhz CML square waveform.
-LMX2594: Sine source channel3 to feed 125Mhz at inputs of the LMX2594; LMX2594 would output a 3.2Ghz differential square waveform.

Note:
The clock sinewave source i have is multi channels,
each channels can be program at any frequency 200Mhz or less,
each channel can be programmed independently as single ended or differential or differential with AC Coupling.
Each channel Vdifferential voltage can be program up to 1 Volts peak-peak.
Each channel has Vcommon mode programmable from 0 to +3V dc

I post to E2E as requested by TI Support   refers to case ID CS2025072 


Thanks
Pat.

  • 0
    TI__Expert 8171 points

    Pat,

    I will get back to you tomorrow.

    Regards,

    Will

  • 0
    TI__Expert 8171 points

    Pat,

    Note that the datasheet for the LMK00334 does not list CML as an output type.  If CML is your desired output you may want to look for a buffer that supports CML outputs such as the CDCL1810 

    Which inputs I should route to (preferred for best performance, lowest jitter)?

    • LMK1D1208/LMX2594 - It does not matter which you choose, same performance.  

    Should I use differential or single ended, or should I used differential with AC coupling for my sine source channel config?

    • Single Ended system will have one trace, more prone to EMI noise
    • Differential signals have more EMI noise immunity and can have a higher swing, but uses two traces 
    • LMX2594 - Input must be AC-coupled, and in general a high slew rate and lower amplitude signal, such as LVDS can give best performance
    • LMK1D1208 - Based on the design tradeoffs you can decide, all things equal, differential may have slightly better performance.  But ensure optimized jitter you will want to see which one of your sinewave output sources (single ended or differential) offers the best jitter performance on its own, and use that.  

    Voltage programming (Vdiff, Vcom, etc) for sine source i should use = ? (for best performance) ?

    • Vcom should not impact performance as long as it is within the specification range.  You could also look at each devices internal Vcom and match that.  
    • For Vdiff, increasing Vdiff may result in a higher slew rate which in turn will result in better performance.  Test to see if increasing Vdiff increases your slew rate, and in that case, maximize Vdiff within the device specifications.  

    Regards,

    Will

  • 0 in reply to William Pfennigwerth
    Prodigy 10 points

    Hi William, when are you available today (NY time) to do an eMeeting to review and discuss this ?      Thanks, just send me by email and email address i can invite to an eMeeting. thanks

  • 0 in reply to Patrice Ducharme
    TI__Expert 8171 points

    Pat,

    I sent you an email.

    Regards,

    Will

  • +1 in reply to William Pfennigwerth
    TI__Expert 8171 points

    Pat,

    I will update you when I get feedback from our synthesizer Applications Engineer.  

    Regards,

    Will

  • 0 in reply to William Pfennigwerth
    TI__Expert 8171 points

    Pat,

    Resolved over email, I am closing the thread.

    Regards,

    Will