• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 34 subscribers
  • Views 2575 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.

DS90UB954-Q1: Power Over Coax Ferrite Bead Selection

Jared Becker
Genius 11945 points

Part Number: DS90UB954-Q1
Other Parts Discussed in Thread: DS90UB960-Q1

Hi Team,

In the EVM user's guide, there are several ferrite beads used to implement power over coax:

Do the ferrite beads have to be those exact values of resistance? What is the consequence if the resistance values are different?

Thank you!

Jared

  • 0
    TI__Expert 8165 points
    Hello Jared,

    The goal of the PoC filter is to make the impedance of the PoC delivery network much higher than the impedance of the 50-ohm transmission line so that the high speed signal edges don't "see" the PoC network. If the impedance of the network is too low (<1kohm for the frequency band of interest), the PoC network would load the transmission line resulting in the transmission line's impedance mismatches, signal reflections, reduced timing and noise margin (eye diagram opening), and ultimately bit errors.

    I suggest reviewing PoC section in the DS90UB960-Q1 datasheet. There are also training modules at training.ti.com/.../

    Regards,
    Davor