Radio frequency variable gain amplifier with linearity insensitive to gain
AssigneeBroadcom Corporation
InventorsLi Lin, Arya Reza Behzad
Life of this patent
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Abstract
A multi-stage, variable gain amplifier whose linearity is relatively insensitive to variations in gain control is disclosed. The amplifier includes a primary cascoded pair of transistors for producing a primary output current from an input voltage as a function of a primary cascode control voltage. The amplifier further includes one or more secondary cascoded pairs of transistors coupled to the primary cascoded pair of transistors for producing one or more secondary output currents from the input voltage as a function of one or more secondary cascode control voltages. The output current of the RF circuit is a sum of the primary output current and the one or more secondary output currents.
Claims22
An RF circuit comprising:
- first means for producing a primary output current from an input voltage as a function of a primary control voltage;
- second means for producing a secondary output current from the input voltage as a function of a secondary control voltage;
- third means coupled to the first means for applying a primary bias voltage to the first means;
- fourth means coupled to the second means for applying a secondary bias voltage coupled to the second means;
- fifth means coupled to the first and second means for summing the primary output current and the secondary output current into an output current of the RF circuit;
- wherein the secondary bias voltage differs from the primary bias voltage.
An RF circuit comprising:
- a primary cascoded pair of transistors for producing a primary output current from an input voltage as a function of a primary cascode control voltage;
- a primary capacitor coupled between the input voltage and the primary cascoded pair of transistors;
- a primary bias voltage coupled between the primary capacitor and the primary cascoded pair of transistors;
- a secondary cascoded pair of transistors coupled to the primary cascoded pair of transistors for producing a secondary output current from the input voltage as a function of a secondary cascode control voltage;
- a secondary capacitor coupled between the input voltage and the secondary cascoded pair of transistors;
- and
- a secondary bias voltage coupled between the secondary capacitor and the secondary cascoded pair of transistors.
Dependencies are inferred from the claim text.