• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 21 subscribers
  • Views 683 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.

Original question:

CDCLVP111-SP: CDCLVP111-SP, TID radiation data

CDCLVP111-SP: AC spec

Michael T Schneider
Expert 3790 points
Part Number: CDCLVP111-SP


Team, can you help with the below?

We use an OSC with LVDS outputs (VOD = 250mV min, 450mV max) to drive the clock input of the CDCLVP111-SP running at 2.5V VCC. The spec states 0.5V VID min with a note 1 states  (1) VID minimum and maximum is required to maintain AC specifications, actual device function tolerates a minimum VID of 100 mV.

 

  1. What is the impact of the AC spec if VID does not meet the 0.5V VID min. Note: LVDS VOD typical is 350mV?
  2. We want to run the part with 2.5V VCC and use the outputs to drive LVDS inputs with DC coupling, what is the recommended termination/bias circuit should we use?

  • 0
    TI__Genius 14540 points
    1) What is the impact of the AC spec if VID does not meet the 0.5V VID min. Note: LVDS VOD typical is 350mV?
    [CY] I would imagine that additive jitter increases at some level below the nominal VOD.

    2) We want to run the part with 2.5V VCC and use the outputs to drive LVDS inputs with DC coupling, what is the recommended termination/bias circuit should we use?
    [CY] Spec calls for VCM of 1V-2.2V which has mid point of 1.55V. This is the most ideal VCM allowing for maximum swing. A resistor divider with 82ohms from VDD to input and 132ohms from input to ground yields DC bias point of 1.55V while presenting 50ohms single-ended to the oscillator. Ensure that the oscillator can operate at 1.55V VCM on its output. If not, I recommend AC coupling.

    thanks
    Christian