LM53603-Q1: LM53603 can not output a constant frequency PWM when its output inductor changed larger

Hello

     We are using LM536035 as a 12V to 5V power supply.When we use the reference design,the DCDC works fine,but the EMC parameters are not good in  frequency multiplication.

     When we change the value of output inductor,the EMC parameters get better,but at this time ,the output PWM frequency gets instability as follow:

     How can we choose the values of peripheral components,are there any methods to caculate these values.

     Thanks a lot.