Quick Datasheet Interpretation - TI LM1084
The device is rated at 5A. It has a current limit (for fault protection) with a typical value of 8A and minimum 5.5 (a little over its rated current). The device will then be thermally limited, so you need to provide heat sinking for the power that it dissipates. Power * Rth j-a gives the die temperature rise above ambient. Rth j-a = Rth j-a (die to case) + Rth c-a (case to ambient). As @uint128_t pointed out you power level is very high. The device will overheat in practical situations with your application.