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kyle.tingey
Visitor II
December 4, 2018
Solved

What is the PLL lock time for the ST25RU3993?

  • December 4, 2018
  • 1 reply
  • 999 views

When trying to frequency hop on the main PLL, I observe a lock time of ~150ms. This seems quite high and I can't find any more information in the datasheet on the matter. Is anyone able to verify the PLL lock time?

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Best answer by Bart Herse

Hello,

In case the PLL is already locked to a certain frequency re-locking to a new frequency depends on the frequency and the frequency hopping step, nevertheless the locking time should be below 500µs.

For start-up the locking time is longer and again depending on the target frequency. Expect a locking time around 800µs.

All above is concerning cases at which the VCO segment is manually chosen.

In case a procedure which is using the Automatic VCO Range Selection (A4h) command is implemented, then the overall locking time is longer since the command A4h itself is taking up to 6 ms to complete, reporting the optimal VCO segment.

Cheers,

B

1 reply

Bart Herse
Bart HerseBest answer
Visitor II
January 9, 2019

Hello,

In case the PLL is already locked to a certain frequency re-locking to a new frequency depends on the frequency and the frequency hopping step, nevertheless the locking time should be below 500µs.

For start-up the locking time is longer and again depending on the target frequency. Expect a locking time around 800µs.

All above is concerning cases at which the VCO segment is manually chosen.

In case a procedure which is using the Automatic VCO Range Selection (A4h) command is implemented, then the overall locking time is longer since the command A4h itself is taking up to 6 ms to complete, reporting the optimal VCO segment.

Cheers,

B