Common-source common-gate amplifier and common-emitter common-gate amplifier

Abstract

The present invention discloses a common-source (common-emitter) common-gate amplifier. The common-source (common-emitter) common-gate amplifier comprises a common-source (common-emitter) transistor, a common-gate transistor, an output load and a substrate biasing circuit. The common-source (common-emitter) transistor receives an input signal. The common-gate transistor sends an output signal and is connected to the output load. The amplifier has a substrate end to which the substrate biasing circuit is connected. As compared with the prior art, the present invention realizes a common-source (common-emitter) common-gate amplifier circuit with a separately biased substrate. The back-gate effect of a common-gate device is eliminated so as to improve the amplifier gain, and a direct connection between a source of the common-gate device and the substrate is also avoided so as to increase parasitic capacitance Cgb from the substrate to the gate, thereby improving the bandwidth and the gain of the amplifier. In addition, since the present invention introduces a reconfigurable biasing circuit, the linearity / noise / stray properties of a signal processing channel are balanced during the circuit switching, a good balance between flexibility and complexity is achieved, and significant improvements are made to the power consumption and area.

Description

technical field [0001] The invention relates to the technical field of amplifier circuits, in particular to a cascode amplifier and a cascode amplifier. Background technique [0002] Amplifiers are generally used for radio frequency or high frequency signal amplification, and different types of amplifiers can be used for different purposes. A wireless communication device, such as a cellular telephone, may include a transmitter and a receiver for two-way communication. The transmitter can use a pre-amplifier (PPA, Pre-PowerAmplifier) ​​and power amplifier (PA, PowerAmplifier), the receiver can use a low-noise amplifier (LNA, LowNoiseAmplifier), and the transmitter and receiver can use a variable gain amplifier (VGA, VariableGainAmplifier) ​​to adapt the gain of the receive path or the output power of the transmit path. [0003] Cascode or cascode amplifiers are widely used in radio frequency and analog amplification due to their good input-output isolation, high output imp...

AI Technical Summary

Problems solved by technology

[0005] In the cascode or cascode structure, the substrate of the cascode tube is usually connected to the source stage to increase the transconductance, thereby increasing the gain of the amplifier, but it will increase the parasitic capacitance Cgb, see figure 1 ; Another common way is to connect the substrate of the common-gate tube to ground, which can reduce the parasitic capacitance, but due to the influence of the back gate effect, the transconductance is reduced, thereby reducing the amplifier gain, see figure 2

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