• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 3 answers
  • Subscribers 32 subscribers
  • Views 665 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

DS90UB921-Q1: power over coax_921&940

Mike Wang2
Intellectual 2760 points
Part Number: DS90UB921-Q1

hi team,

ds90ub921 and ds90ub940 can both support coax cable according to datasheet. Thus, is power over coax supported if using 921+940 pair?

thanks,

Mike

  • 0
    TI__Mastermind 30515 points

    Mike,

    yes, UB921/940 is fine tuned for coax cable application, it means the link design can compensate the coax cable loss etc.

    For PoC, it is one application topic. in general, the PoC would introduce few noise (dependent on PoC circuit design). If both a and b can be met, you can use PoC from application view point.

    a. If your link design can tolerate it (with margin); b. the PoC circuit can select the suitable inductors / FB (based on PoC requirements).

    best regards,

    Steven

  • 0 in reply to Steven(Shenzhen) Shi
    TI__Intellectual 2760 points
    Steven,

    I'm wondering whether we have verified PoC on 921+940 ourselves, or anyone used them before?
    What's the recommended inductors/FB especially for 921+940? Please send me the typical circuits for this application

    Thanks.

    BR,
    Mike
  • 0 in reply to Mike Wang2
    TI__Mastermind 30515 points
    Mike,
    1. dependent on the application condition, if UB940 is used in the display panel side, due to high power consumption in display I/f board, it is hard to design the PoC circuit as no suitable inductor and FB can catch this need. So currently as we know our customers had NOT used >1A PoC application.
    2. regarding the PoC circuit design, please refer to on-line video on PoC in www.ti.com, the PoC network can be designed as similar as UB933/934's as they have similar Back channel rate and close FC rate. but as mentioned, for UB921 and UB940's PoC, the key challenge is that there is NO suitable high current (>1A) 100uH inductor from inductor vendor, such as Murata, Coilcraft due to ferrite's limitation.

    best regards,
    Steven