Hi Team,
There is a section I didn't understand in the datasheet 7.3.13.2 describing the maximum slew rate of the automatic ramping must be kept less than 250kHz/us.
The example given 7.3.13.2.2 just below this section shows a 2GHz ramp within 2ms which is 2MHz/us by excluding the calibration time.
Is there an error or I'm missing something?
Thanks for your help,
BR,
XL
Hi XL,
The 250kHz/µs requirement was based on some assumptions, I need to check with the original author for the details.
Basically, the slew rate is limited by the loop filter bandwidth because the bandwidth will affect PLL lock time. If slew rate is high, we also need a wider loop bandwidth to support.
For example, in below simulation, VCO frequency can make a 2MHz change in less than 1µs.
a smaller loop bandwidth will take a longer time make a 2MHz change.
