Laxmi,
The symbol in LTSpice would not do you any good for simulation without a model to simulate the device. LTSpice can generate the symbol from the model file automatically (see the LTSpice forum for more information on how to do this) from the PSpice model. The PSpice model that TI provides in the product folder is encrypted and can only be used in PSpice version 15.7 or higher.
You will need to request an unencrypted model. Please contact your direct TI support for more information. If you do not have a direct TI support contact, please follow the instructions from the following post:
http://e2e.ti.com/support/development_tools/webench_design_center/f/234/t/36943.aspx
Please note that some of the encrypted PSpice models may require and NDA to obtain the unencrypted model.
Britt