• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 22 subscribers
  • Views 331 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:

LMK04828: Start the SYSREF pulser from CLKin0

LMK04828: Status of Output Pins at Startup

Taito Takemura
Expert 3370 points
Part Number: LMK04828


Hi teams,

Could you please tell me what the output pin status of the LMK04828 is when it starts up, before it runs in the user program?

Background

I am considering connecting DCLKout0/0* on pins 1 and 2 of the LMK04828 to the receiver side via LVDS. At that time, the power supply voltage on the receiver side is 2.5V, which is different from the power supply for the LMK04828. We are concerned that the input rated voltage on the receiver side may be exceeded depending on the order.

Regards,

Taito Takemura

  • 0
    TI__Genius 9260 points

    Hi Taito,

    Our response will be delayed due to US holidays on February 20, 2023. Please expect a response on the following day.

    Best,

    Asim

  • 0
    TI__Genius 10995 points

    Hello Taito,

    Taito Takemura said:
    Could you please tell me what the output pin status of the LMK04828 is when it starts up, before it runs in the user program?

    To directly answer your question, the default output pin status is to be enabled on the LMK04828 at start-up.

    However, to clarify based on your background statement, are you wondering if a signal inputted to the LMK04828 of 2.5-V will damage/affect the device? If that's the case, then the device will be able to handle that voltage, as shown below:

    However, make sure to provide a voltage swing with the below characteristics based on you application:

    If this does not answer your question, please provide a visual to see what's being inputted into the system.

    Best,

    Andrea

  • 0 in reply to Andrea Vallenilla
    TI__Expert 3370 points

    Hi Andrea,

    Thank you for your answer.

    I have an additional question about LMK04828. Could you please answer it? 

    They're considering using 43/44 pin OSCin/OSCin* with a single-ended connection to the clock. Could you please tell me the input impedance of pin 43?

    Thank you for your help.

    Regards,

    Taito Takemura

  • 0 in reply to Taito Takemura
    TI__Genius 10995 points

    Hello Taito,

    Why do you need to know that information? I would need to reach out to the designer for it. If you are wondering how to properly how to connect those pins for single-ended operation please look at picture below (p. 104 of data sheet). 

    Hope this helps!

    Best,

    Andrea