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CDC5801A: CDC5801A

Sutej Torvi
Prodigy 200 points
Part Number: CDC5801A
Other Parts Discussed in Thread: LMK00306, LMK04906

Hi.

We were planning to use CDC5801A clock multiplier with X4 configuration.

The LVDS output will be used to drive a buffer LMK00306.

Will the buffer support LVDS input with 100 Ohm termination from output of CDC5801A?

Also is there any software to simulate the performance of clock multiplier and buffer?

Thanks,

Sutej Torvi.

  • 0
    TI__Genius 12560 points

    Hi Sutej,

    LMK00306 support universal inputs including the LVDS and it's required input swing starts from 0.15V p-p. 

    It can accept the LVDS input from CDC5801A.

    Regards,
    Ajeet Pal

  • 0 in reply to Ajeet Pal
    Prodigy 200 points

    Hi Ajeet,

    Thank you. Have some following questions too.

    As per the Datasheet of CDC5801A, the output swing is 1.7V to 2.9V.

    Will this be the output swing of LVDS output too?

    The 100 Ohm termination is required at input of LMK00306?

    And if the output swing is as per Datasheet, then do we need ac coupling from output of CDC5801A or DC coupling will be sufficient?

    Thanks,

    Sutej Torvi.

  • 0 in reply to Sutej Torvi
    TI__Genius 12560 points

    Hi Sutej,

    All the available buffer have Vid range up to 1.3V, which doesn't meet the output range from CDC5801A.

    You may would need to have some level conversion using transformer or some op-amp based attenuator to meet the buffer requirement.

    Regards,

    Ajeet Pal 

  • 0 in reply to Ajeet Pal
    Prodigy 200 points

    Hi Ajeet.

    Thanks for confirmation and suggestion.

    If LVCMOS output either though AC/DC coupling is given to single ended input of LMK00306, that input level should be fine to use without any attenuation?

    Alternatively, can you suggest me some other clock multipliers with similar specifications which can be integrated with LMK00306 without any level conversion?

    Thanks,

    Sute Torvi.

  • 0 in reply to Sutej Torvi
    Prodigy 200 points

    Hi Ajeet, 

    The specification for frequency at input is from 40MHz to 50MHz. We need a 4X configuration clock multiplier.

    Thanks,

    Sutej Torvi.

  • 0 in reply to Sutej Torvi
    TI__Genius 12560 points

    Hi Sutej,

    Sutej Torvi said:
    If LVCMOS output either though AC/DC coupling is given to single ended input of LMK00306, that input level should be fine to use without any attenuation?

    If VID is below than 1.3V, it should be ok to input at LMK00306. but LVCMOS has higher range, which would affect the performance.

    Unfortunately, we doesn't have such clock multiplier. But I would be surprise to use CDC5801A, which has jitter around 2.1 ps and then LMK00306 for multiple buffered outputs

    I would be recommending to use an jitter cleaner device (LMK04906), which can generate the multiple required frequencies with low jitter performance.

    Please have a look.

    Regards,

    Ajeet Pal

  • 0 in reply to Ajeet Pal
    Prodigy 200 points

    Hi Ajeet.

    Sure will check the LMK04906 clock multiplier.

    Thank you.

    Sutej Torvi.