Hi Prakash BJ,
Can you read the value that you have written for the output divider associated with the output that you are viewing? For example output divider 0 (Reg 0x0190) should be written with a 0xDD. Writing 0xBB would give you 28MHz outputs assuming your reference is 24MHz.
An easy way to verify your settings and generate new ones is to use the evaluation board software and AD9520 configuration tool. Below is a screenshot of my settings and a link to the configuration tool and evaluation board software.
Regards,
Kyle