A linearized and low noise CMOS mixer with B‐type amplifier‐based sub‐harmonic balun

Abstract

SUMMARYA low noise and high linearity down-conversion CMOS mixer for 2.4-GHz wireless receiver is presented in this paper. Using a sub-harmonic balun with a simple but effective B-type amplifier, the local oscillator frequency required for this mixer has been reduced by half, and the input local oscillator signal could be singleended rather than differential, which simultaneously simplifies the design of local oscillator. A distortion and noise cancelation transconductor in association with current bleeding technique is employed to improve the noise and linearity of the entire mixer under a reduced bias current without compromising the voltage gain. Fabricated in a 0.18-μm RF CMOS technology of Global Foundries, the mixer demonstrates a voltage gain of 15.8 dB and input-referred third-order intercept point of 6.6 dBm with a noise figure of 2.6 dB. It consumes 7.65 mA from a 1.0-V supply and occupies a compact area of 0.75 × 0.71 mm 2 including all test pads.

Design and optimization of a CMOS IC novel RF tracking sensor

“…The LO input takes the single‐ended signal from Ant‐LO (50Ω impedance), and it is converted to a differential signal for the GCM by the BALUN circuit. Other approaches to implement BALUNs have also been reported, such as a B‐type amplifier‐based sub‐harmonic BALUN 10 or a transformer based system 11 . Figure 8 shows the schematic of the designed on‐chip BALUN circuit which is implemented based on the combination of cascode CS and CG amplifiers.…”

“…The first and second signal terms in (10) cancel each other out at the operating frequency f c , and the real term (g m /c gs )L S is matched to the 50Ω antenna. The buffer stage M4 is designed for 50Ω output impedance matching.…”

A lumped‐element balun design with multi‐interference suppression for push–pull power amplifier

“…[11], and the active subharmonic balun in ref. [12]. Most of the baluns are basically focused more on the in‐band operation.…”