- 易迪拓培训,专注于微波、射频、天线设计工程师的培养
关于晶体负载电容参数选取问题
仿真一下看你外部时钟线上的分布电容吧!
You can use it have a try.
(CL)=C1*C2 /(C1+C2)+ CS ,andC1 =C2 .(CL) value come from componentspac
The capacitors C1 and C2 form the load capacitance for the crystal. The optimum load capacitance (CL) for a given crystal
is specified by the crystal manufacturer. The equation to calculate the values of C1 and C2 is
Where CS is the stray capacitance on the printed circuit board, typically a value of 5pf can be used for calculation
purposes. Now C1 and C2 can be selected to satisfy the above equation. Usually C1 and C2 are selected such that they
are approximately equal. Large values of C1 and/or C2 increases frequency stability but decreases loop gain and may
cause start-up problems.
非常感谢两位的指点!
3楼的公式是正确的。
另外还是需要楼主根据实际测量下再确定最后的值。
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