Design And Implementation Of Low Power And High Linear Active Elliptic Filters

Filter is an important component of the radio frequency (RF) transceiver highly integrated on chip. Low power and high linearity are two key points of the integrated active filter design. This thesis proposes a low power and high linearity Gm-C filter to the application on the RF front-end of mid-high speed Wireless Sensor Network (WSN), and the filter takes the seventh-order ellipse passive filter as prototype and is designed using TSMC0.13?m RF CMOS process. The layout area of the filter is574?m×618?m, and the post simulation result shows that the cut-off frequency of the filter is4MHz, the typical current under1.2V supply is2.7mW, the1dB compressive point is-4.9dBm, the in-band ripple is less than1dB and the stop-band rejection rate is60dB. The main work and innovation of this thesis are listed as follows:1. An integrated active Gm-C ellipse filter with the passive ellipse filter as prototype is realized in this thesis. The passive inductor is replaced by an active inductor based on Gm-C circuit. In this paper, the circuits and layouts of Gm unit, bias circuit, and filter have been realized and optimized.2. The constant-gm bias circuit is used as the bias circuit of the filter to simplify the circuit structure and reduce the area and power dissipation of the tune circuit while keeping relatively good self-adapted characteristic. The simulation results show that the variation is less than6.5%in the temperature variety region.3. The linear region of differential Gm unit is relatively small with low power supply which limits the dynamic range of the filter. The source degeneration technique is used in this thesis to improve the linearity and increase the input voltage range of Gm amplifier which restrains the cross modulation part and optimizes the linearity of the filter.