about the design of vco
时间：04-10
整理：3721RD
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hi!
i am a freshman in vco.i thought it maybe was easy just to make the vco oscillate.but i find it is not.i use the classical lc tank oscillator.i hope the vco oscillates with the center frequency of 1.4G. i do not consider phase noise,gain and tune range.i just want the vco to oscilltor first.my design process as follows:
i choose a inductor L,whose Q is acceptable.then i compute the parellel resistance and the capacitance C needed to cancel the inductor.then i choose dc current and mosfets whose gm is three times larger than the equal conduntance of the lc tank.then i compute the parasictic capacitance of the mosfet to choose the appropriate vactor.i refere to some ieee papers.i can not find what is wrong.i use candence to do simulation.
who can give me some advice!?hanks a lot
i am a freshman in vco.i thought it maybe was easy just to make the vco oscillate.but i find it is not.i use the classical lc tank oscillator.i hope the vco oscillates with the center frequency of 1.4G. i do not consider phase noise,gain and tune range.i just want the vco to oscilltor first.my design process as follows:
i choose a inductor L,whose Q is acceptable.then i compute the parellel resistance and the capacitance C needed to cancel the inductor.then i choose dc current and mosfets whose gm is three times larger than the equal conduntance of the lc tank.then i compute the parasictic capacitance of the mosfet to choose the appropriate vactor.i refere to some ieee papers.i can not find what is wrong.i use candence to do simulation.
who can give me some advice!?hanks a lot
go to page 23
http://www.cadence.com/whitepapers/oscnoise.pdf
check this
http://www.zen118213.zen.co.uk/RFIC_...Oscillator.pdf
khouly
VCO not oscillating?
oscillation frequency wrong?