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Quad LVDS buffer with enable pin

Kepcoate
Prodigy 140 points

Other Parts Discussed in Thread: LMK01010, LMK00308, CDCUN1208LP, LMK00304, CDCLVD1204, SN65LVDS104

Hi,

I have an application where an LVDS clock  signal needs to be buffered and branched to four LVDS clocks going to four slots. Each slot may or may not be populated. So there is a need to have enable feature on the four LVDS clock signals. Can anybody suggest a part for that? The clock is 100MHz and skew allowed is 100ps.

Thanks

  • 0
    TI__Mastermind 32575 points

    LMK01010 can support 100 MHz, meet your skew requirements, and has very low additive jitter due to very low noise floor (-155 dBc/Hz at 100 MHz).  It has 8 LVDS outputs, but the unused outputs can be powered down.  The output channels also support divide and delay functions (optional).  It is configurable via MICROWIRE serial interface, which is a subset of SPI.

    You might also consider LMK00308 (LMK0030x family) which has 4 output/bank and 2 banks with separate bank enable (not individual buffer).

    Regards,
    Alan

  • 0
    TI__Mastermind 20900 points

    Hello Kepcoate,

    CDCUN1208LP has the possibility to en/disable outputs individually, but it has 8 outputs. the positive part is, that it is a low power device, which can run with 1.8V/2.5V/3.3V or any mixture. It can be configured to HCSL, LVCMOS, LVDS or mixed type outputs.

    if 8 outputs are to much you still have the possibility to use a simple buffer like LMK00304 or CDCLVD1204 with an assembly option. You could place 2x 0-ohm resistor next to the outputs and if the output is not used you place a 100ohm on the pad next to the device between positive and negative output.

    Best regards,

    Julian

  • 0 in reply to Julian Hagedorn
    Prodigy 140 points

    Just want to clarify the requirement. The enable pin is needed for each output separately rather than a bank enable. If a card is not populated in the slot then the option to disable the clock should be there. CDCUN1208LP has one enable for all the clock per the block diagram on first page of its spec. Other devices do not meet the individual enable pin requirement either. Any other recommended parts?

    Thanks.

  • 0 in reply to Kepcoate
    Mastermind 7395 points

    What about SN65LVDS104?

  • 0 in reply to Avi Chami1
    Prodigy 140 points

    This part seems to meet the requirements. Thanks a lot.

  • 0 in reply to Alan O
    Prodigy 10 points

    Has anyone had trouble communicating with the LMK01010 via microwire? I'm sending commands to it, two 16 bit words while chip select is low, and it doesn't seem to be responding. Clock phases and polarities all look right. The problem could also be the clock we're sending to it isn't being read.