【摘要】 采用单层多晶硅 3.3V,0 .35μm CMOS数字工艺 ,实现了用于蓝牙系统的自适应带通滤波器 ,其中心频率为2 MHz,带宽为 1.2 MHz,功耗为 12 m W.并对滤波器 PL L自适应电路中压控振荡器 (VCO)的谐振条件进行了研究 ,分析了 VCO中运放寄生参数对谐振频率的影响 .同时 ,用一种简单的跨导运放结构作为 VCO中的负阻抗 ,解决了VCO振荡幅度限幅问题 .更多还原

【Abstract】 Based on 3.3V,0.35μm,and single-poly CMOS digital process,a bandpass filter(B PF) with on-chip automatic tuning system used in bluetooth system is presented. The center frequency of the filter is 2MHz.The bandwidth is 1.2MHz and its powe r consumption is only 12mW.The resonant condition of voltage controlled oscillat or (VCO) in phase locked loops,which is used in auto-tuning circuit of integra ted filter,is analyzed.The effect of operational transconductance amplifiers’ pa rasitic parameters on VCO’s resonant frequency is studied as well.By using a sim ple operational transconductance amplifier (OTA) as a negative impedance used in VCO,the problem of confining VCO’s oscillation to a desired range is solved.更多还原