A controlled oscillator circuit includes an amplifier including a first transistor coupled between a first node and a reference node, and a second transistor coupled between a second node and the reference node. The gate of first transistor and the gate of the second transistor may be cross-coupled. The oscillator may also include one or more variable capacitance circuits coupled between the first node and the second node, each including a first capacitor coupled between the first node and a third node, and a second capacitor coupled between the second node and a fourth node. Each variable capacitance circuit may also include a third, a fourth and a fifth transistor interconnected to selectively couple the first and second capacitors to the reference node. The third, fourth and fifth transistors may be low voltage transistors and the first and the second transistors may be high voltage transistors.
