What shall I do to stablize the Vcon of VCO to make my PLL work well?

[eda_range]

Hi

My PLL ckt works well in 125°, but while the temperature decending to -40° the ckt can not lock the freq and phase.

What shall I do to stablize the Vcon of VCO to make my PLL work well?

thank you

 

[A.Anand Srinivasan]

Re: a problem on PLL

please post your circuit of VCO... i mean post the circuit of the parts which show variation in output due to temperature,,,....

 

[rogerynt]

Re: a problem on PLL

Hi,

Did you try thermister or use negative temperature coefficient cap. for temperature compensation ?

Rogernt

 

[John Miles KE5FX]

Re: a problem on PLL

You didn't give many details, but check the harmonics of your VCO at the colder temperature. Some PLLs that don't have harmonic-locking problems at room temperature can develop them at high or low temperatures when the VCO's behavior changes.

Also look for issues with moisture condensation. Clean the board thoroughly.

 

[northeast1]

Re: a problem on PLL

Hi

My PLL ckt works well in 125°, but while the temperature decending to -40° the ckt can not lock the freq and phase.

What shall I do to stablize the Vcon of VCO to make my PLL work well?

thank you

your PLL phase margin is not good, you can increase the PLL open loop phase margin.