• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 22 subscribers
  • Views 448 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.

LMX2594: SYSREF pin

[FAE] Andrew Wang
Genius 10685 points
Part Number: LMX2594
Other Parts Discussed in Thread: LMX2595

Hi Team,

Customer have a design question for both LMX2594 and LMX2595.

 If they don’t use SYSREF and ramping mode function.

How to design below pins :

(1)   Pin 5 - SYNC

(2)   Pin 28 - SysRefReq

(3) Pin 30 - RampCLK

(4) Pin 32 – RampDir

Leave it open or ground it with resistor? How big?

Thank you!

Andrew

 

  • 0
    TI__Expert 5325 points
    Hello Andrew,
    a colleague will support you!

    Best regards,
    Patrick
  • 0
    TI__Mastermind 28021 points
    Andrew,

    For these unused pins, they are disabled if powered down. You can float them or ground them back to the center DAP.

    I'm not a fan of grounding through a resistor as the routing for this device is critical and putting resistors and vias close to the chip compromise the layout for other things, such as the RF outputs. The placement of the pull-up component close to the chip for these RF outputs is extremely critical and hard enough; I don't see the need t complicate things more by adding unnecessary routing.

    Regards,
    Dean