What is the best VCO configuration for PLL CDR?

[eng_islam]

Best VCO configration

plz could someone told me what is the best LC VCO configration to be used in PLL CDR i m working on .18 u tech and it is require to work in 2.5 GHZ range

thnx

 

[khouly]

Re: Best VCO configration

the best configration as far as i know hajimari configration which is two nmos cross coupled , and pmos cross coupled

just it , but u must optimize the w and l of transistors and the tank circuit to achive ur phase noise requirments

wish this help

khouly

 

[eng_islam]

Re: Best VCO configration

thanx khouly i want to ask did u try the Emad hegazi filtering tech.
also someone told me that Hajimiri topology not so great than the ordinary method when u use pmos as a current source

 

[husseinadel]

Re: Best VCO configration

thanx khouly i want to ask did u try the Emad hegazi filtering tech.
also someone told me that Hajimiri topology not so great than the ordinary method when u use pmos as a current source

i want the answer of this question urgently , please if anyone tries Hajimiri topology when using pmos as a current source?