LTC7801 issues

I have designed a circuit using LTC7801 to output 12V and 20A at full load. However, the IC failed (BG and GND shorted) when output was just 12V, 3.8A. I am using AUIRF3710ZS MOSFETs in high side and low side for the application. The IC turns itself off when the output approaches 12V and 3.8A, probably due to overheating. The device datasheet however, mentions operation up to 20A. Can someone help me out with this? The schematic and values are as suggested in LTPowerCAD, for the said output. 

changed title
[edited by: JValeriani at 7:55 PM (GMT 0) on 31 Jul 2019]