CMOS down-conversion mixer

Abstract

The invention discloses a CMOS down-conversion mixer. The CMOS down-conversion mixer comprises a radio frequency differential input circuit and a switching circuit. Load circuits formed by connecting resistors and PMOS transistors in parallel are connected between the normal phase output end of the switching circuit and a supply voltage and between the reversal phase output end of the switching circuit and the supply voltage; grid electrodes of the PMOS transistors of the load circuits are connected with a first control voltage, and therefore load impedance of the load circuits can be adjusted. Drain electrodes of two NMOS transconductance tubes of the radio frequency differential input circuit are respectively connected with a constant current source, and source electrodes of the NMOS transconductance tubes of the radio frequency differential input circuit are jointly connected with an LC parallel circuit. According to the CMOS down-conversion mixer, gains can be improved and are adjustable, the linearity and the noise performance can be improved, and the working voltage can be reduced.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit, in particular to a CMOS down-conversion mixer. Background technique [0002] The radio frequency (RF) front end of the wireless transceiver mainly completes the function of frequency conversion in essence. The RF front end of the receiver converts the received RF signal into a baseband signal, and the RF front end of the transmitter converts the baseband signal to be transmitted into a radio frequency signal. Frequency conversion The function is performed by the mixer. The mixer is an important module in the RF front-end circuit. It is a nonlinear circuit that relies on the nonlinearity of the circuit itself to complete the frequency conversion function. A down-converting mixer converts a received RF signal to a lower frequency, called an intermediate frequency (IF). It can be seen that the multiplication produces an output signal at the sum and difference of the frequencies of the input si...

AI Technical Summary

Problems solved by technology

[0006] like figure 1 Compared with the single-balanced mixer, the existing CMOS Gilbert down-conversion mixer shown has good isolation performance, especially the isolation performance from the local oscillator to the intermediate frequency port is improved, and the linear range is larger in addition, but with The further development of the process and the expansion of the application field put forward more application requirements for the performance of the mixer, and objectively require a higher performance mixer

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