Adaptive Power-Supply Regulation for PLLs

[rania_hassan]

adaptive power supply

Dear All,
Could you please, help me to understand this topic Adaptive Power-Supply Regulation for PLLs
Thanks
Rania

 

[khouly]

mm , it seems interesting topic , i don't about it

but i think it is related to that the PLL in aquastion phase can be feed with very regulated voltage but this source can source high current due to charge pump current , but as the PLL coming close 2 lock require the regulator to be very good and the noise in power supply is minimum 2 get the best phase noise and jettier performance , and so the regulator current will be less
so the regulator change from phase 2 phase ,

is this what u talking about or not ?

khouly

 

[rania_hassan]

AA ya Kholy
It's about using regulated supply for some block in the PLL like the VCO
Thanks
Rania

 

[khouly]

yeah in some PLLs the VCO usually biased from a bias cell , spcially the tail current in the cross coupled pair

about the VDD of the VCO , to should be regulated to minimize the noise coupling from the supply to the oscillator output

and this regulaots should be LDO's , coz in technologies the supply is already very low also the VCO should have it is own regulator , also u need to add some form of de coupling capacitors which can be done one chip by using MOS transistor as a capacitor

khouly

 

[rania_hassan]

Thanks very much
Rania

 

[khouly]

if u have anything regarding the PLL , we can share the info an knowledge

khouly

 

[rania_hassan]

Sure, Thanks again