Designer’s Guide Community

Pages: 1

Low - Noise Oscillator Design - Topology selection ?? (Read 2409 times)

Mayank Community Fellow Offline Posts: 334	Low - Noise Oscillator Design - Topology selection ?? Nov 01^st, 2009, 10:16pm Hi everyone, I have to design a low-noise voltage-controlled oscillator. Specs :--- Oscillation Freq. = 1GHz Voltage Supply -- 1.2 Noise requirements -- around -55dBc @10kHz or lower Max. Current Consumption @ 1.2 supply <= 2.5mA. Any Suggestions please ?? --mayank.
Back to top	IP Logged

raja.cedt Senior Fellow Offline Posts: 1516 Germany	Re: Low - Noise Oscillator Design - Topology selection ?? Reply #1 - Nov 1^st, 2009, 10:28pm hi mayank, i feel Phase noise spec seems very tough to achieve with ring oscillator so i feel LC is better but whats your Kvco or Tuning range. Thanks, rajasekhar.
Back to top	IP Logged

Mayank Community Fellow Offline Posts: 334	Re: Low - Noise Oscillator Design - Topology selection ?? Reply #2 - Nov 1^st, 2009, 10:44pm Hi, Kvco is not a problem...Can be adjusted in both Ring Osci...as well as LC[LC offers low Kvco's v easily]..LC easily gives these specs..but it crosses the Area Limit...can't use so much Si real estate :( Can't Ring Osci's satisfy these specs ?? --mayank.
Back to top	IP Logged

raja.cedt Senior Fellow Offline Posts: 1516 Germany	Re: Low - Noise Oscillator Design - Topology selection ?? Reply #3 - Nov 1^st, 2009, 10:51pm hi, certainly you can do with ring oscillator but power you have to consider, so what i am suggesting is build some ring oscillator and vary power and check whether you are meeting power spec or not. I feel all these can be appreciated by simulation..not by any thing else Thanks, rajasekhar.
Back to top	IP Logged

Mayank

Community Fellow

Offline

Posts: 334

Re: Low - Noise Oscillator Design - Topology selection ??
Reply #4 - Nov 1^st, 2009, 10:58pm

Hi,
I have already tried out different topologies in RO design...Not achieving results, That's why i brought this up to the forum.
I have already tried out current-starved CCO, Differential CCO, CML topologies...All of them offer Low phase Noise at Lower Frquencies, but none of them are meeting my noise specs at around 1GHz....What i want to be sure is -- Are these topologies capable of giving such noise performance at given power levels & i am not designing them correctly , Or I can rule out ROs and go for LC?

Just wanna be sure to rule out Ring Osci....

regards,
Mayank.

IP Logged

Pages: 1

‹ Previous topic | Next topic ›