• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 22 subscribers
  • Views 906 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.

LMK04828: the Vpp of clkout is low

user5147995
Prodigy 50 points

Part Number: LMK04828
Other Parts Discussed in Thread: ADS54J66

when i use lmk04828  to program a 300MHz DCLK signal with LVDS.

i can get accurate frequency, but it's Vpp only 400mv.what's more,With the increase of frequency, the Vpp decreases.

is this normal? what may case this?

  • 0
    TI__Expert 8865 points
    Hi user5147995 ,
    Are you using EVM from TI or a custom board? What termination you have for this output?
    Are you measuring 400mV swing single ended on each of the two differential output pins or this is a differential swing and you have only 200mV on each pin?
    Best regards
    Puneet
  • 0 in reply to Puneet Sareen
    Prodigy 50 points

    think you

    i use a custom board, the clkout  connect to ads54J66, i have only 200mV on each pin which is out of range according to the datasheet.

    now,i can get an accurate frequency and the DAC lock signal is ok.

    which pin or register will infiuences this?

  • 0 in reply to user5147995
    TI__Expert 8865 points
    Hi user5147995,
    Please post your output termination schematics for this output and the registers you are programming. DCLKoutx_FMT registers defines the output type. Please make sure that LVDS is programmed there.
    Best regards
    Puneet