適用於超寬頻無線通訊之高速五階轉導-電容濾波器設計

Abstract

本論文完成一適用於超寬頻無線通訊之濾波器設計，以五階elliptic低通濾波器來達成最窄的過渡頻帶(transition band)，整個濾波器是用轉導、電容組成並採取低敏感度的LC階梯型電路，其中轉導電路使用對稱及非對稱差動對來改善線性度，以及負電阻技巧來增加差模輸出電阻，濾波器之全諧波失真(Total Harmonic Distortion)在0.52V峰對峰訊號下有-40dB，輸入相關雜訊電壓為211.8uVrms，當考慮20MHz輸入訊號時，動態範圍(Dynamic Range)為58.4 dB，消耗的功率在1.8-v的供應電壓下為32.25mW其中包括12.1mW的輸出緩衝器，質優值(Figure-of-Merit)為59.75dB，此設計是以聯電0.18微米製程來實現，為了方便量測，整個電路是採用矽品所提供之QFN系列包裝，並以印刷電路板做為量測模組，量測結果頻寬為226MHz，增益為-4.07dB通帶起伏(ripple)為1.32dB，功率消耗為43.2mW。

A 5th order CMOS high frequency elliptic low pass filter is designed to achieve narrowest transition band. The filter is composed of Gm blocks and capacitances. The symmetrical & unsymmetrical differential pair increases Gm linearity, and negative impedance increases Gm differential output resistance. The total harmonic distortion (THD) of this filter is -40dB within 0.52Vp-p. Input-referred noise is 211.8uVrms. Dynamic range is 58.4dB for 20MHz input. The power consumption of filters is 32.25mW (include 12.1mW output buffer) from 1.8V supply. The figure-of-merit for the filter is 59.75dB. The filter is implemented in UMC 0.18-μm CMOS technology and has been packaged in SPIL QFN20 which is mounted on PCB board in favor of measurement. The f3db is 226MHz and gain is -4.07 dB with 1.32 dB passband ripple. The power dissipation of this filter is 43.2mW.