• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 20 subscribers
  • Views 1226 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.

LMX2594: LMX2594 full assist VCO calibration and the lock dected of the MUXOUT function

user3753555
Prodigy 50 points
Part Number: LMX2594

Dear TI experts,

    Refer to LMX2594/95 application note draft -Fast frequency switching using the "full assist" mode" to configure the LMX2594, register write data "0X002514", turn off the VCO Calibration function, select the VCO Calibration and VTUNE lock detect function output on the MUXOUT pin. Output 3 frequency points: 1014.344MHz, 1071.844MHz and 1297.874MHz. With the spectrum and signal analyzer test results, the frequency and phase noise are normal.


      Problem: 1. Why MUXOUT output is always low, which means that the output signal is not locked, but the signal analyzer detects that the signal is locked;


                    2. The FCAL_EN of R0 is set to 1. When the signal is locked, MUXOUT can output a high level.

regards,

  • 0
    TI__Guru* 81510 points
    Hi there,

    In full assist mode, you don't need to disable FCAL, you can keep FCAL_EN=1.
    Lock detect will check for VCOcal complete as well as Vtune, if both of these factors meet the threshold, LD will turn HIGH.
    When FCAL_EN=0, VCOcal will be 0 and therefore LD will always LOW.