High-linearity low-noise transconductance amplifier

Abstract

The invention discloses a low-noise transconductance amplifier, which is specifically of a differential input / output structure. Each of a left side circuit and a right side circuit comprises two branches of complementary common source cascades, a feedback cascade comprising a complementary source cascade follower and resistors, and a load cascade; after a differential radio frequency input signal enters input ports Vin<+> and Vin<->, the signal is converted into a current signal by two branches of NMOS / PMOS complementary common source tubes at the left side and the right side, and the current signal is transmitted to output nodes IO<+> and IO<->; output currents at the left side and the right side respectively pass through the left load cascade and the right load cascade to be converted into a differential output voltage signal, and the differential output voltage signal is converted into a current signal after passing through the left feedback cascade and the right feedback cascade and flows into the input ports Vin<+> and Vin<->, so that input impedance matching is realized. A forward access and a feedback access both adopt NMOS / PMOS transistor complementary symmetrical structures to realize current reuse and good linearity, and small signal and big signal linearity of the transconductance amplifier and anti-barrage jamming capacity can be remarkably improved in a relatively wide frequency band.

Description

Technical field [0001] The invention belongs to the field of integrated circuits, and particularly relates to a high linearity low noise transconductance amplifier. Background technique [0002] In recent years, people's urgent demand for high data rates has greatly stimulated the research, development and application of multi-mode and multi-band radio frequency receivers. Traditional multi-mode and multi-band receivers use receiving front-end circuits optimized for each frequency band, resulting in a larger chip area and power consumption (shortened battery life). At the same time, in the face of great out-of-band interference (such as 0dBm out-of-band interference specified by the GSM standard), off-chip bulky surface acoustic wave (SAW) filters are commonly used, such as figure 1 As shown in (a), this further increases the board size and overall cost. In order to reduce hardware costs as much as possible and achieve single-chip integration, figure 1 The structure of the SAW-f...

AI Technical Summary

Problems solved by technology

However, the inherent second-order nonlinear interaction of the feedback circuit deteriorates the linearity of traditional active feedback low-noise amplifiers, which cannot meet the increasingly stringent linearity performance requirements of today's wireless systems

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