[SOLVED] Question about VCO gain

[ruwan2]

Hi,
I read a paper about VCO design in an IC. It is 1.8 V supply. The VCO frequency gain is 270 MHz/V. When I try to simulate in Matlab, I find it has problems. The 1.8 V has maximum only frequency range of 270 * 1.8=486 MHz. How can it reach 3.128 GHz of its goal?
Is my understanding wrong? I cannot find another VCO gain definition yet?

Thanks,

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I got it from a similar post, see below please. It is about relative range. Thanks,

https://www.edaboard.com/threads/150499/

For instance, it you have a 3 volt power supply, and you need to tune from 2 to 2.3 GHz, you need more than 100 MHz per volt for the vtune range available to cover the entire band.

 

[tompham]

I think we measure VCO gain in the range frequency linearity with vtune or vcontrol only. Let say the linearity range from 2v to 2.5v you have VCO frequency 2G and 2.3G , so the VCO gain will be (2.3-2)/(2.5 - 2) = 600Mhz/V