Analog Devices,inc.

Stephen Jonathan Brett

Jonathan Richard Strange

Paul Fowers

Christopher Geraint Jones

A frequency agile voltage controlled oscillator is provided in which amplitude control is performed by digitally controlling the current supplied to the oscillator from a current source (). The use of digital control means that phase noise performance of the oscillator is not degraded by the introduction of noise from the current source controller.

Voltage controlled oscillator having improved phase noise

A circuit protects differential inputs of circuitry, such as RF circuitry, against electrostatic discharge. The circuit includes first and second diodes connected in opposite directions between a first differential input pin and a virtual ground node, third and fourth diodes connected in opposite directions between a second differential input pin and the virtual ground node, a first protection device connected between the virtual ground node and a first external pin, such as a positive supply pin, and a second protection device connected between the virtual ground node and a second external pin, such as a negative supply pin. The first and second protection devices may be fifth and sixth diodes, respectively. Because no signal appears at the virtual ground node, the fifth and sixth diodes can be relatively large.

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Hailsham, United Kingdom

Stephen Jonathan Brett