System and method for voltage-controlled oscillator calibration

1. A method comprising:

determining frequency control information relating to output frequency of a voltage-controlled oscillator (VCO), wherein:

the VCO output frequency varies based on changes in one or more operational conditions; and

the frequency control information enables indicating the VCO output frequency within a range of allowable values for one or more control inputs and a range of expected values based on the one or more operational conditions;

for each of one or more control input settings, determining based on the frequency control information, calibration control information for determining a calibration voltage associated with at least one of the one or more control inputs, with respect to the one or more operational conditions, to generate a corresponding constant VCO output frequency;

assessing the one or more operational conditions;

determining, based on at least one of the one or more control inputs, a calibration voltage corresponding to the assessed one or more operational conditions;

applying the calibration voltage;

determining, based on applying the calibration voltage, a tuning control input for tuning the constant VCO output frequency; and

applying the tuning control input to the VCO.

2. The method of claim 1 , wherein the one or more operational conditions comprise a junction temperature of the VCO.

3. The method of claim 1 , wherein the one or more operational conditions comprise a power supply voltage of the VCO.

4. The method of claim 1 , wherein the one or more operational conditions comprise an on-die humidity of the VCO.

5. The method of claim 1 , wherein the one or more operational conditions comprise a junction temperature of the VCO and a power supply voltage of the VCO.

6. The method of claim 1 , wherein the one or more control inputs comprise a coarse-tuning control input and a fine-tuning control voltage input.

7. The method of claim 1 , wherein the calibration control information comprises a polynomial function.

8. The method of claim 1 , comprising generating the constant VCO output frequency such that the constant VCO output frequency is a midpoint of a usable VCO frequency range that comprises all VCO output frequencies that can be generated at a particular control input setting, over all of the range of expected values of the one or more operational conditions using only allowable values of a particular control input.

9. The method of claim 1 , wherein tuning the constant VCO output frequency comprises minimizing a difference between the constant VCO output frequency and a target frequency.

10. The method of claim 1 , wherein the voltage-controlled oscillator (VCO) of a phase-locked loop (PLL) system, and further comprising placing the PLL system in an open-loop state before applying the calibration voltage.

11. A system comprising:

a voltage-controlled oscillator (VCO); and

one or more circuits operable to:

determine frequency control information relating to output frequency of the VCO, wherein:

the VCO output frequency varies based on changes in one or more operational conditions; and

the frequency control information enables indicating the VCO output frequency within a range of allowable values for one or more control inputs and a range of expected values based on the one or more operational conditions;

for each of one or more control input settings, determine based on the frequency control information, calibration control information for determining a calibration voltage associated with at least one of the one or more control inputs, with respect to the one or more operational conditions, to generate a corresponding constant VCO output frequency;

assess the one or more operational conditions;

determine, based on at least one of the one or more control inputs, a calibration voltage corresponding to the assessed one or more operational conditions;

apply the calibration voltage;

determine, based on applying the calibration voltage, a tuning control input for tuning the constant VCO output frequency; and

apply the tuning control input to the VCO.

12. The system of claim 11 , wherein the one or more operational conditions comprise a junction temperature of the VCO.

13. The system of claim 11 , wherein the one or more operational conditions comprise a power supply voltage of the VCO.

14. The system of claim 11 , wherein the one or more operational conditions comprise an on-die humidity of the VCO.

15. The system of claim 11 , wherein the one or more operational conditions comprise a junction temperature of the VCO and a power supply voltage of the VCO.

16. The system of claim 11 , wherein the one or more control inputs comprise a coarse-tuning control input and a fine-tuning control voltage input.

17. The system of claim 11 , wherein the calibration control information comprises a polynomial function.

18. The system of claim 11 , wherein the one or more circuits are operable to control the VCO such that the constant VCO output frequency is a midpoint of a usable VCO frequency range that comprises all VCO output frequencies that can be generated at a particular control input setting, over all of the range of expected values of the one or more operational conditions using only allowable values of a particular control input.

19. The system of claim 11 , wherein the one or more circuits are operable to minimize a difference between the constant VCO output frequency and a target frequency when tuning the constant VCO output frequency.

20. The system of claim 11 , wherein:

the voltage-controlled oscillator (VCO) is associated with a phase-locked loop (PLL); and

the one or more circuits are operable to place the PLL in an open-loop state before applying the calibration voltage.