Method and apparatus for control of a digital phase locked loop (dpll) with exponentially shaped digitally controlled oscillator (dco)

An integrated circuit comprising:

• a plurality of first transistor units fixedly coupled to an input voltage;
• a plurality of second transistor units switchably coupled to the plurality of first transistor units;
• and
• an output electrically coupled to the plurality of second transistor units and the plurality of first transistor units to convey an output signal having a frequency dependent on which select ones of the second transistor units are enabled, wherein an increase in the frequency of the output signal due to a selected one of the second transistor units being enabled is proportional to a width of transistors in the selected one of the second transistor units,
• wherein the plurality of second transistor units include:
• a first switchable transistor unit having at least one transistor of a first width,
• a second switchable transistor unit having at least one transistor of a second width greater than the first width, and
• a third switchable transistor unit having at least one transistor of a third width greater than the second width.