Tropian, Inc.

Reme, L.l.c.

Jerold Lee

A high bandwidth operational amplifier architecture has three control loops, which are combined via a voltage-follower-configured field effect transistor. The first control loop is an instantaneous main amplification path and employs positive feedback-based Vgs correction of the output transistor. The second control loop has a bandwidth considerably lower than the first loop and employs negative feedback to correct for long term drift errors. The third control loop, utilizing negative feedback, is a fast path having a bandwidth that overlaps the bandwidth of the first control loop, and corrects for overshoot and undershoot in the main amplification path.

High power, wide bandwidth operational amplifier

The present invention, generally speaking, allows for a substantial reduction in oscillator phase noise by modifying the transfer function of a portion of the oscillator, e.g., by adding a zero to the transfer function. Modifying the transfer function reduces the open-loop gain of the oscillator but achieves a desired phase compensation, allowing the oscillator to be operated at the resonance of the resonator instead of off resonance. In an exemplary embodiment, the transfer function is modified by choosing a capacitance value such that, instead of operating as a bypass at the frequency of interest, adds a zero to the transfer function of the oscillator and causes a change in frequency characteristics, achieving an increase in the effective Q of the oscillator. This increase in effective Q translates directly into reduced phase noise. Phase noise improvement in the range of 3dB has been demonstrated.

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Los Altos, CA, United States of America

Jerold Lee