Sam,
Thanks for your feedback, it worked :-) . I have removed the compensation network and replaced ceramic capacitors with tantalum. Now the buzzing noise was reduced nearly 90%. I have only 10% of noise.
I have a concern is it advisable to use T491D106M050AT as input capacitor, because it has 800mohms of ESR. But I'm not sure whether it will cause any problems. With the online TI simulation tool, I found that it suggests capacitors below 25mohms to be used with this regulator. But for my design it costs pretty high. so will it be advisable to use 800mohm ESR capacitor in the input?
-Sathiya
