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US 6,122,497 AGranted
RF mixer with inductive degeneration
AssigneeAnalog Devices, Inc.
InventorBarrie Gilbert
Life of this patent
Estimating the term…
Abstract
An RF mixer provides extended dynamic range with reduced noise by utilizing degeneration inductors in the RF input section of a doubly balanced mixer. Degeneration inductors are also utilized in a mixer having a class AB input section. A current mirror in the class AB input section is also inductively degenerated for further noise reduction. The input section is biased by an all-NPN bandgap reference cell which is tightly integrated into the input section so as to reduce the power supply voltage required for the reference cell. The mixer can be optimized for wide input voltage ranges or low distortion.
Claims22
An RF mixer comprising:
- a mixer core having an LO port for receiving an LO signal, an IF port for providing an IF output signal, and an input port having first and second input terminals for receiving first and second current signals;
- and
- an RF input section coupled to the input port for providing the current signals responsive to an RF input signal;
- wherein the RF input section includes:
- a first transistor coupled to the first input terminal,
- a second transistor coupled to receive the RF input signal, wherein the second transistor is diode-connected,
- a third transistor coupled to the second transistor and the second input terminal and arranged to form a current mirror with the second transistor, and
- an inductor coupled to the first transistor to extend the dynamic range of the mixer;
- and
- wherein the first transistor is configured for operation in common base mode.
7 more elements
An RF mixer comprising:
- a mixer core having a first input terminal for receiving a first current signal and a second input terminal for receiving a second current signal;
- a first subcell coupled to the first input terminal of the mixer core to provide the first current signal to the mixer core responsive to an RF input signal, the first subcell having a first transistor and a first inductor coupled to the first transistor to extend the dynamic range of the mixer;
- and
- a second subcell coupled to the second input terminal of the mixer core to provide a second current signal to the mixer core responsive to an RF input signal, the second subcell having a second transistor and a second inductor coupled to the second transistor to extend the dynamic range of the mixer;
- wherein:
- the first transistor includes a first terminal coupled to the first input terminal, a second terminal coupled to receive a reference signal, and a third terminal;
- the inductor includes a first terminal coupled to the third terminal of the first transistor and a second terminal coupled to receive the RF input signal
- the second transistor is diode connected;
- and
- the second inductor is arranged to degenerate the transconductance of the second transistor;
- and
- wherein the second subcell further includes a third transistor coupled to the second transistor and the second input terminal and arranged to form a current mirror with the second transistor.
9 more elements
A current mirror comprising:
- a first transistor having a first terminal for receiving an input signal, a second terminal coupled to the first terminal of the first transistor to cause the first transistor to operate as a diode, and a third terminal;
- a first inductor coupled between the third terminal of the first transistor and a common node to reduce the noise of the current mirror;
- a second transistor having a first terminal for transmitting an output signal, a second terminal coupled to the first terminal of the first transistor, and a third terminal;
- and
- a second inductor coupled between the third terminal of the second transistor and a common node to reduce the noise of the current mirror.
2 more elements
An RF amplifier comprising:
- a first transistor coupled between a first node and a common node in a diode configuration;
- a second transistor having a first terminal for transmitting an output signal, a second terminal, and a third terminal coupled to a second node;
- a passive component coupled between the first and second nodes;
- a delta-Vbe cell referenced to the common node and having first and second load input terminals for loading the cell, and a sense terminal coupled to the first node for sensing the voltage across the first transistor;
- and
- a third transistor having a first terminal coupled to the common node, a second terminal coupled to the second load input terminal, and a third terminal coupled to the second terminal of the second transistor to provide a bias signal to the second transistor.
3 more elements
An RF input section for a mixer, the RF input section comprising:
- a first output terminal for coupling a first current to a mixer core;
- a second output terminal for coupling a second current to the mixer core;
- a first transistor having a first terminal coupled to the first output terminal, a second terminal coupled to receive a bias signal, and a third terminal;
- a first inductor coupled between the third terminal of the first transistor and an RF input terminal for receiving an RF input signal;
- a diode;
- a second inductor, wherein the diode and the second inductor are coupled in series between the RF input terminal and a common node;
- and
- a second transistor having a first terminal coupled to the second output terminal, a second terminal coupled to form a current mirror with the diode, and a third terminal coupled to the common node.
5 more elements
An RF input section for a mixer, the RF input section comprising:
- a first output terminal for coupling a first current to a mixer core;
- a second output terminal for coupling a second current to the mixer core;
- a first transistor having a first terminal coupled to the first output terminal, a second terminal coupled to receive a bias signal, and a third terminal coupled to a first RF input terminal for receiving a first RF input signal;
- a first diode coupled between the first RF input terminal and a common node;
- a second transistor having a first terminal coupled to the second output terminal, a second terminal coupled to form a current mirror with the first diode, and a having a first terminal coupled to the first output terminal, a second terminal coupled to receive a bias signal, and a third terminal coupled to an RF input terminal for receiving an RF input signal;
- a first diode coupled between the RF input terminal and a common node;
- a second transistor having a first terminal coupled to the second output terminal, a second terminal coupled to form a current mirror with the diode, and a third terminal coupled to the common node;
- a third transistor having a first terminal coupled to the second output terminal, a second terminal coupled to receive the bias signal, and a third terminal coupled to a second RF input terminal for receiving a second RF input signal;
- a second diode coupled between the second RF input terminal and the common node;
- a fourth transistor having a first terminal coupled to the first output terminal, a second terminal coupled to form a current mirror with the second diode, and a third terminal coupled to the common node.
7 more elements
A current mirror comprising:
- an input terminal;
- an output terminal;
- a common terminal;
- a diode-connected transistor;
- a first inductor, wherein the diode-connected transistor and the first inductor are coupled in series between the input terminal and the common terminal;
- a second transistor having a first terminal coupled to the diode-connected transistor to form a current mirror with the diode-connected transistor, a second terminal coupled to the output terminal, and a third terminal;
- and
- a second inductor coupled between the third terminal of the second transistor and the common terminal.
5 more elements
Dependencies are inferred from the claim text.