How to simulate a LC VCO?

[benever]

how to simulate a LC VCO


thanks!

 

[khouly]

Re: VCO design

with which tool , and what kind of simulation u want
u want tuning range , or phase noise , oscillation start up , pushing , and pulling

khouly

 

[eeliuliu]

Re: VCO design

you can get the help from cadence document.

Added after 3 minutes:

with which tool , and what kind of simulation u want
u want tuning range , or phase noise , oscillation start up , pushing , and pulling

khouly

hi, khouly,
Could you please tell us how to simulate pushing and pulling?
I never do that before. thanks a lot!

 

[benever]

Re: VCO design

with which tool , and what kind of simulation u want
u want tuning range , or phase noise , oscillation start up , pushing , and pulling

khouly

cadence spectre such as tuning range , or phase noise , oscillation start up

the characteristic performance of a LC VCO

THANKS

 

[khouly]

Re: VCO design

check this link
www.cadence.com/community/virtuoso/resources/SpectreRF_VCO533AN.pdf
also check this link for ADS
**broken link removed**

khouly

 

[benever]

Re: VCO design

another question, when i design the LC VCO with the technics of TSMC .18um,

I am sorry to find that the Q of the inductor is lower but the series resisance is not lower as i want ,
then the Gm of the mos is not as large as i want ,

so the VCO can not work ,at a fixed current.

how can i do ?

thanks

check this link
www.cadence.com/community/virtuoso/resources/SpectreRF_VCO533AN.pdf
also check this link for ADS
h**p://www.zen118213.zen.co.uk/RFIC_Circuits_Files/LC_Oscillator.pdf

khouly

Added after 1 minutes:

another question, when i design the LC VCO with the technics of TSMC .18um,

I am sorry to find that the Q of the inductor is lower but the series resisance is not lower as i want ,
then the Gm of the mos is not as large as i want ,

so the VCO can not work ,at a fixed current.

how can i do ?

thanks

check this link
www.cadence.com/community/virtuoso/resources/SpectreRF_VCO533AN.pdf
also check this link for ADS
h**p://www.zen118213.zen.co.uk/RFIC_Circuits_Files/LC_Oscillator.pdf

khouly

 

[khouly]

Re: VCO design

gm of MOS device will depend on W , try to increase the W of the cross coupled pair ,
but be sure the extra parasitics they will add won't change ur oscillation frequency

khouly

 

[benever]

Re: VCO design

you are rihgt, to increase W , I've tried ,the W is at the most value ,but the Gm is still the 10-to-13 , and the tail current is not propotional to the fixed current though the setting propotional W/L ,(lower )

i don't know why.

gm of MOS device will depend on W , try to increase the W of the cross coupled pair ,
but be sure the extra parasitics they will add won't change ur oscillation frequency

khouly

Added after 59 seconds:

you are rihgt, to increase W , I've tried ,the W is at the most value ,but the Gm is still the 10-to-13 , and the tail current is not propotional to the fixed current though the setting propotional W/L ,(lower )

i don't know why.

gm of MOS device will depend on W , try to increase the W of the cross coupled pair ,
but be sure the extra parasitics they will add won't change ur oscillation frequency

khouly

Added after 39 seconds:

you are rihgt, to increase W , I've tried ,the W is at the most value ,but the Gm is still the 10-to-13 , and the tail current is not propotional to the fixed current though the setting propotional W/L ,(lower )

i don't know why.

gm of MOS device will depend on W , try to increase the W of the cross coupled pair ,
but be sure the extra parasitics they will add won't change ur oscillation frequency

khouly

 

[khouly]

Re: VCO design

pushing , and pulling effect can be simulated

pushing , by sweeping the VDD , and see the effect on oscillation frequency

pulling : by sweeping load capacitance , and check the oscillation frequency

about the W/L , try to adjust the bias point of the cross coupled pair

and try to attach schematic for ur VCO


Khouly