• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 20 subscribers
  • Views 392 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.

Original question:

LMK05028: Can I use LMK05028 as PTP Boundary Clock?

LMK05028: how about the voltage drop from VDDO_X to LVCMOS output

Oliver Ou
Intellectual 2845 points
Part Number: LMK05028

Hi,

Customer wants to know if the LVCMOS output level if VDDO_X is connected to 3.3V.

if LVCMOS can output 3.3V? What is the VDDO_X for this channel at this output condition?

Thanks.

Oliver Ou

  • 0
    TI__Mastermind 30100 points

    Hello Oliver,

    When VDDO_x is 3.3V, the internal LDO regulator limits the swing of LVCMOS to about 2.8V ± 0.1V. We do not characterize the 3.3V LVCMOS output case, so consider my number a typical value only. These numbers are not a guarantee.

    Regards,

  • 0 in reply to Derek Payne
    TI__Intellectual 2845 points

    Hi Derek,

    Thanks a lot for your feedback. Customer also have another question about the 1588 application and need your help.

    --------

    1.1588 Timing chip works in DCO mode. Can we adjust phase under DCO mode? How do you adjust the phase?

    2. What register should be configured with the TICS Pro tool at this condition?

       How to generate configuration files to burn new chip after configuration?

    Thanks again. 

  • 0 in reply to Oliver Ou
    TI__Mastermind 30100 points

    Hi Oliver,

    DCO mode is completely documented in the datasheet section 9.4.4, please reference this. You adjust the phase by adjusting the target PLL output frequency until the desired phase offset is achieved.

    TICS Pro DCO configuration is actually located down the main start page, under the subheader "DCO Mode."

    Instantaneous phase relative to target frequency is given by:

    Phase Change = sum(10^9 / (sDPLLx_DCO_STEP in ppb * DPLLx_FDEV_k * PLLxPDIVy_freq in Hz) * dt_k)

    where dt is the duration spent at a given FDEV step. The suffix _k denotes each step: if the FDEV value is incremented or decremented multiple times, the rate of phase change will be different for each FDEV value, so there are multiple steps in the sum.

    ---

    Once steps 1-6 are configured as desired, check that the reference input monitors have a valid configuration as well. The reference input monitors are just below the main steps in the main page.

    The LMK05028EVM gives a step-by-step guide to connecting to a device. Even if the EVM is not being used, the guide is still valid for connecting TICS Pro to an LMK05028 device on a different board.

    Under the "Advanced" tab in TICS Pro for the LMK05028, there is an EEPROM page which includes the option to export the GUI settings to an EEPROM file. You can program the EEPROM from this page, or by pressing the "Program EEPROM" button on the top bar.

    Regards,