Mindspeed Technologies, Inc.

Skyworks Solutions, Inc.

Rockwell Science Center, Inc.

Kashif A Ahmed

Krishna Shivaram

Frederic M Stubbe

Guangming Yin

Ricke Waylan Clark

Daryush Shamlou

Valentina Della Torre

Various amplifier configurations having increased bandwidth, linearity, dynamic range, and less distortion are shown and disclosed. To increase bandwidth in a transimpedance amplifier, a replica circuit is created to replicate a degeneration resistance, or the resistance or value that relates to a feedback resistance. From the replica circuit, the replicated values are mirrored and processed to control a FET switch which modifies a degeneration resistance. The FET switch control signal is related to the feedback resistance and modifies the degeneration resistance to thereby maintain the product of the feedback resistance and the degeneration resistance as a constant. In another embodiment, a second switch controlled by an automatic gain control signal is established between a first stage amplifier and a second stage amplifier to improve dynamic range and bandwidth without degrading other amplifier specifications.

Variable gain amplifier

Linear transimpedance amplifier with wide dynamic range for high rate applications

A system of and method for reducing or eliminating any unwanted sideband component in the output of a transmitter comprising a quadrature modulator followed by a translational loop. In one implementation, a value representative of the unwanted sideband is derived from a low frequency signal generated within or by the translational loop. In this implementation, the low frequency signal is taken from an input to a VCO within the translational loop.

System of and method for reducing or eliminating the unwanted sideband in the output of a transmitter comprising a quadrature modulator followed by a translational loop

A converter for converting a single-ended input V.sub.IN to a differential output signal V.sub.OUT through positive and negative output terminals is disclosed. The converter comprises a fully differential amplifier with one of its input terminals coupled to the single-ended input and its other input terminal coupled to a fixed voltage. The converter also has a first resistor ('R.sub.1 ') coupled between the single-ended input and the positive input terminal of the fully differential amplifier, a second resistor ('R.sub.2 ') coupled between the fixed voltage and the negative input terminal of the fully differential amplifier, a third resistor ('R.sub.3 ') coupled between the positive input terminal and the negative output terminal of the fully differential amplifier, and a fourth resistor ('R.sub.4 ') coupled between the negative input terminal and the positive output terminal, wherein the values of such resistors are governed by: ##EQU1## The same principles can be applied to differential-to-single-ended converters as well.

Single-ended to differential converter with relaxed common-mode input

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Irvine, CA, United States of America

Kashif A Ahmed