Abstract
To have a fully integrated communication system in CMOS, a CMOS bandpass amplifier which combines the functions of low noise amplifier (LNA) and bandpass filter (BPF) is necessary. In a conventional bandpass amplifier, a Q-enhancement circuit is required to compensate for the resistive loss in the integrated inductor. The Q-enhancement circuit, however, being active, increases the power consumption (P sub(d)) and noise figure (NF) of the system. In the paper, a new bandpass amplifier has been proposed which can achieve the required Q without an additional Q-enhancement circuit. Comparison with other recent designs shows that the proposed amplifier has the lowest P sub(d) and the best noise performance. Based on the CSM 0.25 mu m CMOS process, the bandpass amplifier has a gain of 25.3 dB, a Q of 30, an NF of 3.56 dB and a P sub(d) of 35.7 mW at 1.8 GHz.