TI中文支持网Part Number:LMK04821EVM
Hi， Dear,
We use LMK04821EVM to evalute our application, that need 10MHz clock（Using A Rubidium Oscillator） as input reference clock, not use default 122.88MHz clcok.
When we using default 122.88MHz clcok as input clock to OSCIn, the PLL2 show can locked.
But we try switch to 10MHz clock as input to OSCIN, Single PLL. We cann't config the EVB to locked.
So, is there any suggestion or guidance to our seeting? Thanks a lot~
The attached configue:
Input clock： 10MHz， Output Clock：1000MHz，Using VCO1=3000MHz.
logan He：
The configure can refer following. Now PLL2 cannot lock, Is there any thing can improve? Thanks a lot
,
Amy Luo：
您好，
感谢您对TI产品的关注！
为更加有效的解决您的问题，我将您的问题发布在了E2E英文论坛上了，请将有资深的英文论坛工程师为您提供帮助，请耐心等待E2E的回复：
https://e2e.ti.com/support/clock-timing-group/clock-and-timing/f/clock-timing-forum/1131101/lmk04821evm-cannot-be-locked
,
Amy Luo：
E2E已给答复。EVM板上的122.88MHz时钟您是不是没有拆下来？如果是的话，那很可能是这个原因导致PLL无法锁定。
需要修改PCB板电路以使OSCIn与外部参考源配合使用，具体修改连接情况请查看EVM板用户指南末尾处的原理图：
