A Mixer Circuit of CMOS Complementary Structure

Abstract

The invention discloses a mixer circuit of CMOS complementary structure, comprising: four transconductance input stages and a local oscillator pulse shaping stage; when V LO+ , V LO‑ When it is high or low, the first and second transconductance input stages receive V RF+ , V RF‑ Voltage signal, the differential RF voltage signal is amplified and passed to V IF+ , V IF‑ port; when V LO+ , V LO‑ After level flipping, the differential signal goes from V RF+ and V RF‑ The ports are respectively amplified by the fourth and third input transconductance stages and passed to V IF‑ , V IF+ port; the local oscillator pulse shaping stage shapes the single-ended sinusoidal local oscillator signal into a differential rectangular local oscillator signal, which equivalently reduces the power requirements for the sinusoidal local oscillator signal and eases the design pressure on the isolation of the local oscillator port; transconductance input The stage adopts CMOS complementary structure to achieve the effect of current multiplexing and reduce power consumption; and can obtain the second-order nonlinear compensation effect to reduce the influence of second-order interaction distortion.

Description

technical field [0001] The invention belongs to the field of radio frequency integrated circuits, in particular to a mixer circuit. Background technique [0002] The mixer is a key module in the RF receiver, because it completes the frequency conversion of RF-IF and directly determines the architecture of the receiver. In order to reduce the contribution of the mixer and the post-stage circuit noise to the system noise, and to compensate the loss of the IF filter, the mixer needs a certain conversion gain. [0003] Such as figure 1 As shown, the active mixer based on the Gilbert multiplier is widely used in the RF integrated front-end of various architectures due to its high mixing gain and superior port isolation. However, its noise figure is relatively high. The noise of the active mixer mainly comes from the flicker noise of the switching stage, the thermal noise and the thermal noise of the RF transconductance stage (TERROVITIS, M.T., MEYER, R.G. Noise in current comm...

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Problems solved by technology

However, because the tail current transistor needs to work in the triode region, a large AC local oscillator signal is required, which poses a challenge to the performance of the port isolation

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