A CMOS capacitor neutralizing active mixer

Abstract

The invention provides a CMOS capacitor neutralization active mixer, and belongs to the field of mixers. The active mixer comprises a transconductance input stage, a switch mixing stage and an outputload stage, and received radio frequency voltage signals are converted into intermediate frequency voltage signals through the mixer to be output. According to the invention, two capacitor cross coupling circuit units are used in the transconductance input stage in an improved manner, a low noise index is generated, and the two capacitor cross coupling circuit units are connected through an NMOS/PMOS stacked structure, so that the power consumption of the circuit is effectively saved; the bandwidth is effectively enhanced by designing a passive matching network; capacitance neutralization techniques are used for compensating for source-drain electrode parasitic effect of transconductance input stages and loop gain of enhanced transconductance stages, so that the isolation degree and the linearity of the mixer are improved.

Description

technical field [0001] The invention belongs to the field of mixers, in particular to a CMOS capacitor neutralization active mixer. Background technique [0002] Configurable wireless transceivers adapting to multi-band and multi-mode communication protocols are being widely adopted all over the world. In its hardware implementation, the parameter requirements of wideband, low noise and high linearity of the receiver are very important considerations for circuit designers . In a typical receive chain, the down-converting mixer, one of the key building blocks, has a significant impact on the noise and linearity of the receiver. Therefore, the design of the mixer is full of challenges. [0003] While passive mixers are gaining popularity due to their good linearity and low flicker noise, the inherent conversion losses and poor port isolation of such mixers often create larger noise figure and IQ crosstalk issues . In contrast, active mixers have high conversion gain and ex...

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However, because the tail current transistor needs to work in the triode region, a large AC loca

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