如何设计两个连续的PLL

另一种可能性是使用PLL产生60 MHz，然后是DCM。
使用CLK2X，CLK0和CLKDV输出，您可以从DCM同相获得120,60和30 MHz。
-  Gabor
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以下为原文

Another possibility is to generate 60 MHz with a PLL followed by a DCM.  Using the CLK2X, CLK0, and CLKDV outputs you can then get 120, 60, and 30 MHz from the DCM all in phase.
-- GaborView solution in original post

嗨，
您是否在两个PLL之间使用BUFG（从第一个PLL到BUFG的时钟输出再到第二个PLL的输入）？
。
该路径产生较少的抖动。
请参阅http://www.xilinx.com/support/documentation/user_guides/ug382.pdf的第114页。
它有一小部分级联PLL。
检查这是否有帮助。
谢谢，
迪皮卡。
谢谢，迪皮卡.----------------------------------------------
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以下为原文

Hi,
 
Did you use BUFG in between two PLL's (clock output from first PLL to BUFG and then to input of second PLL)? . This path produces less possible jitter.
 
Refer to page-114 of http://www.xilinx.com/support/documentation/user_guides/ug382.pdf . It has a small section of cascading PLL's. Check if this helps.
 
Thanks,
Deepika.
Thanks,
Deepika.
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另一种可能性是使用PLL产生60 MHz，然后是DCM。
使用CLK2X，CLK0和CLKDV输出，您可以从DCM同相获得120,60和30 MHz。
-  Gabor



以下为原文

Another possibility is to generate 60 MHz with a PLL followed by a DCM.  Using the CLK2X, CLK0, and CLKDV outputs you can then get 120, 60, and 30 MHz from the DCM all in phase.
-- Gabor

您使用的是Xilinx CoreGen工具吗？
PLL不稳定有很多安慰。
其中很少列出如下
如果输入时钟不稳定
输入时钟抖动更多
启动序列期间不会释放GTS。
如果电压不稳定。
如果VCCAUX电压出现问题，如噪声尖峰，则取出数据手册中规定的可接受的工作范围。
如果DCM和PLL的复位信号连接在一起，链中的第二个组件将自动等待第一个组件锁定，然后再开始自己的锁定周期。
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以下为原文

Are you using Xilinx CoreGen tools?
 
There many resons for PLL unstabilty. Few of them listed below

• If the input clock is not stable
  
• More Jitter in Input clock 
  
• GTS is not released during the startup sequence.
  
• If suplly voltages are not stable. If some problem in VCCAUX voltage like noise spike which takes out acceptable operating range specified in data sheet.
  
• In case when the reset signals of the DCM and PLL are tied together, the second component in the chain will automatically wait for the first to lock before starting it's own locking cycle.
  

 
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你好
谢谢你的建议，它解决了我的问题。
亲切的问候，
康拉德



以下为原文

Hi
 
Thank you for your advice, it solved my Problem.
 
Kind Regards,
 
Konrad