IMD 상쇄기를 적용한 CMOS 구동 증폭기 선형화 방법

Abstract

We have designed and fabricated a linear drive amplifier with a novel intermodulation distortion (IMD) canceller using 0.18 ㎛ CMOS process. The drive amplifier with IMD canceller is composed of a cascode main amplifier and an additional common-source IMD canceller. Since the IMD canceller generates IM3 (3rd-order imtermodulation) signal with 180° phase difference against the IM3 of the cascode main amplifier, the IM3 power is drastically eliminated. As of the measurement results, OP1dB, OIP3, and power-add efficiency are 5.5 dBm, 15.5 dBm, and 21 %, respectively. Those are 5 dB, 6 dB, and 13.5 % enhanced values compared to a conventional cascode drive amplifier. The IMD3 of the drive amplifier with IMD canceller is enhanced more than 10 dB compared to that of the conventional cascode drive amplifier for input power ranges from -22 to -14 dBm.