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给出了一个 90 0 MHz CMOS锁相环 /频率综合器的设计 ,设计中采用了电流可变电荷泵及具有初始化电路的环路滤波器 .电荷泵电流对温度与电源电压变化的影响不敏感 ,同时电流的大小可通过外部控制信号进行切换控制而改变 .因此 ,锁相环的特性 ,诸如环路带宽等 ,也可通过电流的改变而改变 .采用具有初始化电路的环路滤波器可提高锁相环的启动速度 .另外采用了多模频率除法器以实现频率合成的功能 .该电路采用 0 .18μm、1.8V、1P6 M标准数字 CMOS工艺实现 .
A 90 0 MHz CMOS phase-locked loop / frequency synthesizer design is presented with a current-variable charge pump and a loop filter with an initializing circuit. The charge-pump current is insensitive to temperature and supply voltage variations , At the same time the size of the current can be changed by the external control signal switching control.Therefore, the characteristics of the phase-locked loop, such as loop bandwidth, etc., can also be changed by the current change.Using the loop filter with initialization circuit can be increased Phase-locked loop start-up speed.In addition to the use of multi-mode frequency divider to achieve the function of frequency synthesis of the circuit using 0.18μm, 1.8V, 1P6 M standard digital CMOS technology to achieve.