Inductor-free low-noise amplifier with separated gain and impedance matching

Abstract

The invention discloses an inductor-free low-noise amplifier with separated gain and impedance matching and relates to the technical field of radio frequency integrated circuits. The low-noise amplifier comprises a push-pull amplifier, a voltage buffer and a feedback resistor. The input end of the push-pull amplifier is used as the input end of the low-noise amplifier; the output end of the push-pull amplifier is connected to the input end of the voltage buffer, the output end of the voltage buffer serves as the output end of the low-noise amplifier, and the two ends of the feedback resistor are connected to the output end of the voltage buffer and the input end of the push-pull amplifier respectively. The circuit structure provided by the invention meets the requirements of gain amplification and input impedance matching of the low-noise amplifier at the same time; the problem that feedback resistor of a resistive feedback common-source amplification circuit limits system gain and MOStransistor channel resistance at the same time is avoided, matching between input impedance and a radio frequency receiver antenna is more flexible, the system gain of the circuit is larger, the noise of the amplifier is lower, and the circuit design and implementation difficulty is greatly reduced.

Description

technical field

[0001] The invention relates to the technical field of radio frequency integrated circuits, in particular to a non-inductive low-noise amplifier with separated gain and impedance matching. Background technique

[0002] With the increasing application of the Internet of Things, the demand for wireless communication chips is becoming more and more urgent. In the front end of the RF transceiver, the general non-inductive low noise amplifier (Low Noise Amplifier, LNA) adopts a common source amplifier circuit with resistive feedback, and uses a feedback resistor to feed back a current from the output voltage to the input terminal.

[0003] In order to achieve low-noise amplification, the LNA needs to consider the input impedance matching and amplification gain; the traditional non-inductor LNA uses a common-source amplifier circuit with resistive feedback, and the feedback resistor needs to meet both impedance matching and amplification gain; the RF receiving fron...

Examples

Embodiment 1

[0042] As the first stage of the RF receiver, the low noise amplifier receives and amplifies the RF signal from the RF antenna, in order to reduce the R F simultaneous effects on gain and input impedance, this embodiment provides as figure 2 The shown two-stage circuit structure combines resistive feedback with a voltage buffer (voltage buffer) circuit, and the voltage buffer adopts a source follower circuit structure.

[0043] Such as figure 2 The circuit structure shown consists of three parts:

[0044]1. The first-stage amplifying circuit composed of a push-pull amplifier;

[0045] 2. Voltage buffer level composed of source follower;

[0046] 3. Feedback resistor R F .

[0047] The working process of this embodiment is:

[0048] The signal from the antenna of the RF receiver passes through the impedance matching network to the input terminal V of the first stage amplifier circuit IN , the first stage is used as the main gain stage, the second stage provides the vol...

Embodiment 2

[0069] Such as image 3 As shown, on the basis of Embodiment 1, the first-stage push-pull amplifier in Embodiment 2 adopts a cascode circuit structure, and the circuit performance is better improved when the circuit principle remains unchanged. .

[0070] VCN and VCP are DC bias voltages of MOS tubes MNC and MPC respectively, and MNC and MNS, MPC and MPS respectively form a cascode structure.

technical field

[0001] The invention relates to the technical field of radio frequency integrated circuits, in particular to a non-inductive low-noise amplifier with separated gain and impedance matching. Background technique

[0002] With the increasing application of the Internet of Things, the demand for wireless communication chips is becoming more and more urgent. In the front end of the RF transceiver, the general non-inductive low noise amplifier (Low Noise Amplifier, LNA) adopts a common source amplifier circuit with resistive feedback, and uses a feedback resistor to feed back a current from the output voltage to the input terminal.

[0003] In order to achieve low-noise amplification, the LNA needs to consider the input impedance matching and amplification gain; the traditional non-inductor LNA uses a common-source amplifier circuit with resistive feedback, and the feedback resistor needs to meet both impedance matching and amplification gain; the RF receiving fron...

Examples

Embodiment 1

[0042] As the first stage of the RF receiver, the low noise amplifier receives and amplifies the RF signal from the RF antenna, in order to reduce the R F simultaneous effects on gain and input impedance, this embodiment provides as figure 2 The shown two-stage circuit structure combines resistive feedback with a voltage buffer (voltage buffer) circuit, and the voltage buffer adopts a source follower circuit structure.

[0043] Such as figure 2 The circuit structure shown consists of three parts:

[0044]1. The first-stage amplifying circuit composed of a push-pull amplifier;

[0045] 2. Voltage buffer level composed of source follower;

[0046] 3. Feedback resistor R F .

[0047] The working process of this embodiment is:

[0048] The signal from the antenna of the RF receiver passes through the impedance matching network to the input terminal V of the first stage amplifier circuit IN , the first stage is used as the main gain stage, the second stage provides the vol...

Embodiment 2

[0069] Such as image 3 As shown, on the basis of Embodiment 1, the first-stage push-pull amplifier in Embodiment 2 adopts a cascode circuit structure, and the circuit performance is better improved when the circuit principle remains unchanged. .

[0070] VCN and VCP are DC bias voltages of MOS tubes MNC and MPC respectively, and MNC and MNS, MPC and MPS respectively form a cascode structure.

Images