用於WiMax之互補金氧半類比基頻電路設計

Abstract

本論文針對WiMax無線網路應用提出低功率高動態範圍類比基頻電路之設計。為了達到多頻寬和高增益範圍，我們用了可單級提供30dB增益高範圍的假指數之可變增益放大器(VGA)和可以改變頻寬從0.625 MHz到14 MHz的多頻寬濾波器(LPF)，在這濾波器中是由兩個轉導電路組成的元件合成的。在高動態範圍的架構下，以較少可變增益放大器串接級來達成低功耗和用轉導電容的濾波器來減少所需面積。最後用這VGA和LPF電路設計整個類比基頻電路並分析雜訊、線性度和干擾。經由0.13-μm CMOS 和1.2伏偏壓的製程進行電路實作，這電路可提供86dB的最大功率增益、16dB的最低增益值，並在400mVpp輸出電壓時約可得40dB全諧波失真。

This thesis presents a low-power high dynamic range design of CMOS analog baseband circuitry for WiMax applications. To achieve multi-bandwidth and high gain range, the proposed variable gain amplifier employs a wide-range pseudo-exponential circuit topology providing about 30dB dynamic per-stage, and the proposed LPF(Low Pass Filter) incorporates two adjustable transconductor achieving various cut-off frequency from 0.625MHz to 14MHz. With the proposed topology, the number of amplifier stages can be reduced and the level of power consumption is tremendously lowered, and the gm-c based LPF stage help to reduce area. Base on the proposed VGA and LPF, the topology of analog baseband is analized to consider the trade-offs among noise, linearity and interference. The circuit is implemented in 0.13-μm CMOS process, and provides a maximum forward gain of 86 dB and a minimum forward gain of 16 dB from a 1.2-V supply. The harmonic distortion is 38.19dB under the output signal magnitude is 400m Vpp.