Amplifier

Patent metadata

Field	Value
Publication number	US-10020780-B2
Application number	US-201715419516-A
Country	US
Kind code	B2
Filing date	Jan 30, 2017
Priority date	Feb 4, 2016
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

An amplifier including a first cascode circuit including a first transistor and a second transistor whose source or emitter is coupled to a drain or a collector of the first transistor, a second cascode circuit being a differential pair with the first cascode circuit, the second cascode circuit including a third transistor whose source or emitter is coupled to a source or an emitter of the first transistor and a fourth transistor whose source or emitter is coupled to a drain or collector of the third transistor, a first feedback path that couples between an output terminal of the third transistor and an input terminal of the first transistor, the first feedback path including a first capacitative element, and a second feedback path that couples between an output terminal of the first transistor and an input terminal of the third transistor, the second feedback path including a second capacitative element.

First claim

What is claimed is:

1. An amplifier comprising:
a first cascode circuit including:
a first transistor; and
a second transistor whose source or emitter is coupled to a drain or a collector of the first transistor;

a second cascode circuit that forms a differential pair with the first cascode circuit, the second cascode circuit including:
a third transistor whose source or emitter is coupled to a source or an emitter of the first transistor; and
a fourth transistor whose source or emitter is coupled to a drain or collector of the third transistor;

a first feedback path that couples between an output terminal of the third transistor and an input terminal of the first transistor, the first feedback path including a first capacitative element;
a second feedback path that couples between an output terminal of the first transistor and an input terminal of the third transistor, the second feedback path including a second capacitative element;
a third feedback path that couples between an output terminal of the second transistor and an input terminal of the second transistor, the third feedback path including a third capacitative element;
a fourth feedback path that couples between an output terminal of the fourth transistor and an input terminal of the fourth transistor, the fourth feedback path including a fourth capacitative element;
a fifth feedback path that couples between an output terminal of the fourth transistor and the input terminal of the first transistor, the fifth feedback path including a fifth capacitative element; and
a sixth feedback path that couples between an output terminal of the second transistor and the input terminal of the third transistor, the sixth feedback path including a sixth capacitative element.

2. An amplifier comprising:
a pair of cascode circuits as a differential pair, each cascode circuit including:
a first transistor;
a second transistor whose source or emitter is connected to a drain or collector of the first transistor; and
a feedback path that couples between an output terminal of the second transistor and an input terminal of the second transistor, the feedback path including a capacitative element; and

a pair of capacitative elements and a pair of feedback paths,
wherein one of the pair of the feedback paths is a path on which an output terminal of a second transistor included in one of the cascode circuits forming the differential pair is connected to an input terminal of a first transistor included in the other of the cascode circuits forming the differential pair via one of the pair of capacitative elements, and
wherein the other of the pair of the feedback paths is a path on which an output terminal of a second transistor included in the other of the cascode circuits forming the differential pair is connected to an input terminal of a first transistor included in the other of the cascode circuits forming the differential pair via the other of the pair of capacitative elements.

Assignees

• Fujitsu Ltd

Inventors

• Shimura Toshihiro

Classifications

• H03F3/45179

  using MOSFET transistors as the active amplifying circuit (H03F3/45278 takes precedence) · CPC title

• H03F3/245

  with semiconductor devices only · CPC title

• H03F3/45188

  Non-folded cascode stages · CPC title

• H03F3/193

  with field-effect devices (H03F3/195 takes precedence) · CPC title

• H03F2200/451

  the amplifier being a radio frequency amplifier · CPC title