temperature drift of VCO

[rfmems]

what is the main reason of temperature drift of a cmos lc oscillator

 

[khouly]

as the temp increase the propertise of the FET diferent like the capacitance and the current and so on , and this will make the oscillator change in freq

also the varactor will be affected

khouly

 

[rfmems]

thanks khouly, but I think the inductor makes more contribution on temp drift, isn't it?

 

[khouly]

yeah also the inductor will drift with temperature will also affect the oscillation frequency

khouly

 

[echo47]

The capacitor also has a temperature coefficient. If you are using discrete parts, then you can probably buy a negative temperature coefficient (NTC) capacitor that roughly cancels out the inductor's typically positive temperature coefficient.