Elantec Semiconductor, Inc.

Michael Hopkins

Input stages for use in multiplexing, and methods for using the same, are provided herein. An input stage includes an input terminal and an output terminal. A voltage input signal is accepted at the input terminal of the input stage. When the input stage is selected, a substantially unmodified version of the voltage input signal is presented at the output terminal of the input stage, when the input stage is selected. When the input stage is deselected, a rejection voltage signal is produced, where the rejection voltage signal is of substantially equal magnitude and opposite polarity to the corresponding voltage input signal in order to reject the voltage input signal and thereby present a substantially constant voltage at the output terminal of the input stage regardless of variations in the voltage input signal.

Input stage for multiplexing and methods for using an input stage for multiplexing

A multiplexer circuit includes a plurality of switched differential amplifier circuits, one of which can be selected at a time. Each switched differential amplifier includes a pair of differential inputs and a pair of differential outputs, with each pair of differential inputs accepting a corresponding pair of input signals. Each of the switched differential amplifier circuits is configured to present a current mode version of its input signals at its differential outputs when the switched differential amplifier circuit is selected, and to present substantially zero level output signals at its differential outputs when the switched differential amplifier circuit is deselected. The multiplexer circuit also includes a selector that accepts a select signal and selects one of the plurality of switched differential amplifier circuits based on said select signal. A current mirror is used to combine a pair of multiplexer outputs into a single ended output, a version of which is used for feedback.

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Tracey, CA, United States of America

Michael Hopkins