Patent ID: 6661301
Filing Date: 2003-12-09
Classification: H03B,H03J

Abstract:
An oscillator circuit, comprising:a symmetrically constructed oscillator core with a least one inductance and at least one capacitance forming a resonant circuit with a symmetrical oscillation node; two switchable capacitances connected via a respective terminal to said oscillation node and forming a switching node at free terminals thereof; and a switching unit connected to said switchable capacitances for altering a resonant circuit frequency by activating said switchable capacitances, said switching unit including a first switch for a direct low-impedance connection to one another of said free terminals of said switchable capacitances and further switches for a low-impedance connection of said free terminals of said switchable capacitances to a supply voltage, said first switch and said further switches being MOS transistors and being integrated in a common transistor structure of said switching unit, a source region of one of said further switches also forming a drain region of said first switch, and a drain region of another of said further switches also forming a source region of said first switch.