Methods, apparatus, and systems for a multi-band hybrid inductor-capacitor voltage-controlled oscillator

An inductor-capacitor (LC) oscillator comprising:

• a first inverter having a first terminal and a second terminal coupled to an enable terminal;
• a first core including:
• a first transistor having a control terminal, a first terminal, and a second terminal, the control terminal coupled to the first terminal of the first inverter, the first terminal coupled to a supply terminal;
• a first LC tank circuit including a first inductor and a first capacitor, the first LC tank circuit having a first terminal and a second terminal across which a clock signal is to be measured;
• and
• a second transistor having a control terminal, a first terminal, and a second terminal, the control terminal coupled to the enable terminal, the first terminal coupled to a ground terminal;
• a second inverter having a first terminal and a second terminal coupled to a tuning terminal;
• and
• a second core including:
• a third transistor having a control terminal, a first terminal, and a second terminal, the control terminal coupled to the first terminal of the second inverter, the first terminal coupled to the supply terminal;
• a fourth transistor having a control terminal, a first terminal, and a second terminal, the control terminal coupled to the first terminal of the first LC tank circuit, the first terminal coupled to the second terminal of the third transistor;
• a second LC tank circuit including a second inductor and a second capacitor, the second LC tank circuit having a first terminal and a second terminal, the first terminal coupled to the second terminal of the fourth transistor;
• and
• a fifth transistor having a control terminal, a first terminal, and a second terminal, the control terminal coupled to the second terminal of the first LC tank circuit, the second terminal coupled to the second terminal of the second LC tank circuit;
• and
• a sixth transistor having a control terminal coupled to the tuning terminal, a first terminal coupled to the ground terminal, and a second terminal coupled to the first terminal of the fifth transistor, the first inductor being inductively coupled via a mutual inductance to the second inductor.

A phase-locked loop (PLL) oscillator comprising:

• a phase comparator circuit having a terminal;
• a filter circuit having a first terminal and a second terminal coupled to the terminal of the phase comparator circuit;
• and
• an inductor-capacitor (LC) voltage-controlled oscillator (VCO) including:
• an inverter having a first terminal and a second terminal coupled to the first terminal of the filter circuit;
• a first transistor having a control terminal, a first terminal, and a second terminal, the control terminal coupled to the first terminal of the inverter, the first terminal coupled to a supply terminal;
• a second transistor having a control terminal, a first terminal, and a second terminal, the first terminal coupled to the second terminal of the first transistor;
• an inductor having a first terminal coupled to the second terminal of the second transistor and a second terminal coupled to the second transistor;
• a capacitor having a first terminal coupled to the second terminal of the second transistor and a second terminal coupled to the control terminal of the second transistor;
• a third transistor having a control terminal, a first terminal, and a second terminal, the control terminal coupled to the first terminal of the inductor and the first terminal of the capacitor, the second terminal coupled to the second terminal of the inductor and the second terminal of the capacitor;
• and
• a fourth transistor having a control terminal coupled to the first terminal of the filter circuit, a first terminal coupled to a ground terminal, and a second terminal coupled to the first terminal of the third transistor.