Voltage controlled oscillator integrated circuit
AssigneeNorthern Telecom Limited
InventorsRonald Douglas Beards, Samuel Alfred Tiller
Life of this patent
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Abstract
A voltage controlled oscillator has a cross-coupled negative resistance cell formed as an integrated circuit connected to off-chip components of a high-Q resonant tank circuit. To counteract spurious oscillations brought about by package parasitics caused by the interconnection of the chip to the external components, the cell is provided with a degeneration impedance. Typically, a pure inductor is used if all the elements of the tank circuit are off-chip. In a case where the tank circuit includes an on-chip fixed capacitor, the degeneration impedance may take the form of a capacitor.
Claims6
A voltage controlled oscillator comprising an integrated circuit on-chip cross-coupled negative resistance cell coupled to a high-Q resonant tank circuit, wherein the resonant tank circuit comprises an on-chip capacitor and an off-chip portion, and wherein a degeneration capacitor is provided in the negative resistance cell to increase the magnitude of the negative resistance presented to the tank circuit at frequencies other than the resonant frequency of the tank circuit and thereby reduce spurious oscillations due to package parasitics.
Dependencies are inferred from the claim text.