LM5145: LM5145 heating up

Part Number: LM5145

Tool/software:

Hi,

Anybody suggests the IC LM5145, Buck Regulator Positive Output Step-Down DC-DC Controller, the reason of heating. The layout side we found through thermal pad via only gnd is connected ground plane. There is no external copper which can help in reduce heating. Is the layout cause any issue or please suggest. FYI, LM5145 Component placed in Bottom. Total 4 layers @ 1.6mm thick Top, ground, power, Bottom

Regards

Vivek

Mob:9632322773