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LMX2594EVM: lmx2594 lock time

yehonatan ben naim
Prodigy 20 points
Part Number: LMX2594EVM
Other Parts Discussed in Thread: LMX2594, USB2ANY

dear team,

i've just recieved the LMX2594EVM

I am triyng to perfome a frequency change of 2 G and measuring long locking time of about 130ms

this value is regarding to the time measured from issuing the FCAL_EN command till the LD rise time.

I expecting to measure much lower values

can you advice me how to reduce the locking time

Thank you

Best regards

Yoni

  • 0
    TI__Expert 5370 points
    dear Yoni,

    thank you for reaching out.

    A couple of things:

    If using the TiCS PRO + USB2ANY combo for controlling, you will have to be careful on how you measure this. The USB2ANY is avery slow so you should not include the spi transaction in this case as very slow. LMX2594 will support 75 MHz spi transaction speed. You may start "counting" when final CSB goes high. You can then add for your final implementation the number of register you need to change times 24 divided by 75e6.

    Also, you may change the setting of the lock detect to capture the calibration time only. Under the page "user controls" section "general controls" set LD_type==VCOcal.

    You should be be able to get around 60 us calibration time.

    Regards, Simon.