Invention Grant
- Patent Title: Low noise class AB linearized transconductor
- Patent Title (中): 低噪声级AB线性化跨导体
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Application No.: US12820807Application Date: 2010-06-22
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Publication No.: US08120426B1Publication Date: 2012-02-21
- Inventor: Marcus Granger-Jones , Jim Connelly
- Applicant: Marcus Granger-Jones , Jim Connelly
- Applicant Address: US NC Greensboro
- Assignee: RF Micro Devices, Inc.
- Current Assignee: RF Micro Devices, Inc.
- Current Assignee Address: US NC Greensboro
- Agency: Withrow & Terranova, P.L.L.C.
- Main IPC: H03F3/45
- IPC: H03F3/45

Abstract:
A transconductor stage is a linearized class AB amplifier having embedded noise filtering that enables a biasing of an in-phase/quadrature (I/Q) modulator core with a low quiescent current. Linearization of the transconductor stage is increased by introducing a small amount of negative feedback into the transconductor stage via a feedback circuitry and an error amplifier. A dominant open loop pole in a path between the error amplifier and an output stage of the transconductor stage forms a dominant pole low-pass filter. A low-pass filter transfer function created when a loop including the feedback circuitry is closed attenuates noise introduced by baseband circuitry that supplies baseband signals to the transconductor stage. A master output stage biases a plurality of slave output stages that are in parallel with the master output stage. Each slave output stage is coupled to an individual modulator core such as a Gilbert cell mixer core.
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