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ADF4118 VCO direct FM modulation circuits

Hi all,

Our customers evaluate the ADF4118 for FM modulation wireless microphone with VCO direct modulation.
When the power supply on/off is evaluated, the PLL lock time may vary.
At this time, confirming each voltage of Charge Pump Power Supply Voltage: Vp, Charge Pump Output Voltage: Vcp,
VP ≤ VCP
It seems to be.

To slow down the response speed of the loop filter, a μF-order capacitor is included in the loop filter circuit.
Apparently, the behavior of Vcp does not completely turn off even if Vp is turned off.

This seems to be a behavior contrary to the following items described in the data sheet.
Compliance range
0.5 V ≤ VCP ≤ VP − 0.5
Can these effects be considered?

We are not familiar with VCO direct FM modulators.
Is it possible that the above phenomena occur in the VCO direct FM modulation circuit configuration?
Could you also advise on how to solve this?

Best regards,

sss