Psemi Corporation

Peregrine Semiconductor Corporation

Hossein Noori

Chih-Chieh Cheng

Various methods and circuital arrangements for complete turn OFF of branches of a multi-branch cascode amplifier are presented. According to one aspect, a protection circuit coupled to a source node of an output transistor of a branch couples a reference voltage to the source node of the output transistor when the branch is turned OFF, and decouples the reference voltage from the source node when the branch is turned ON. According to another aspect, the protection circuit includes a switch whose off capacitance is sufficiently low so as not to affect performance of the branch when the branch is ON, and whose on resistance is sufficiently low to sufficiently reduce an RF amplitude at the source node of the output transistor when the branch is OFF and other branches are ON, and therefore allow use of low-voltage thin-oxide transistors in the branch. Further aspects include a second switch and use of transistor switches.

Complete turn off and protection of branched cascode amplifier

A receiver front end capable of receiving and processing intraband non-contiguous carrier aggregate (CA) signals using multiple low noise amplifiers (LNAs) is disclosed herein. A cascode having a 'common source' input stage and a 'common gate' output stage can be turned on or off using the gate of the output stage. A first switch is provided that allows a connection to be either established or broken between the source terminal of the input stage of each cascode. Further switches used for switching degeneration inductors, gate/sources caps and gate to ground caps for each legs can be used to further improve the matching performance of the invention.

LNA with programmable linearity

A receiver front-end capable of receiving RF inputs having a broad range of levels. The receiver comprises a low-noise amplifier (LNA) operating in a variety of bias modes that cover a large gain range. Branches of the amplifier can be turned on in various combinations to allow selection of different bias modes. A degeneration inductor coupled to the source of the common source FET of each branch has a plurality of taps that are coupled to degeneration switches that can ground the tap to effectively shorten the degeneration inductor and reduce the amount of degeneration inductance. The degeneration inductor and associated switches can be fabricated using one of several physical layouts. Operating the degeneration switches to select the length of the degeneration inductor to match the bias mode reduces changes in the input impedance as different bias modes are selected.

LNA with variable gain and switched degeneration inductor

A selectable low noise amplifier (LNA) system comprising, a plurality of LNAs having a plurality of LNA characteristics and at least one selection switch network coupled to the plurality of LNAs to select at least one of the plurality of LNAs.

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San Diego, CA, United States of America

Hossein Noori