Patent Number: 7,042,272

Title: Transconductance amplifier with substantially constant resistance and mixer using same

Abstract: A transconductance amplifier (620) includes four transistors each operating in saturation and strong inversion. A first transistor (622) has a first current electrode and a control electrode both receiving an input voltage, and a second current electrode coupled to a power supply voltage terminal. A second transistor (624) has a first current electrode, a control electrode coupled to the first current electrode of the first transistor (622), and a second current electrode coupled to the power supply voltage terminal. A third transistor (626) has a first current electrode for providing a negative differential current, a control electrode for receiving a bias voltage, and a second current electrode coupled to the first current electrode of the first transistor (622). A fourth transistor (628) has a first current electrode for providing a positive differential current, a control electrode for receiving the bias voltage, and a second current electrode coupled to the first current electrode of the second transistor (624).

Inventors: Dornbusch; Andrew W. (Austin, TX)

Assignee: Silicon Laboratories, Inc.

International Classification: G06F 7/44 (20060101)

Expiration Date: 5/09/02018