My Requirement is 6V-36V Input, 5V Output, 1A Output, Ambient Temperature is (-40degC to 90degC). When I put this value in Webench Design tool for MPN-LMR36015 I got the the design In that design report for MPN-LMR36015FBRNXR. The IC Power dissipation shown is 887.1mW.
But when i am calculating The allowed power dissipation i.e. Pd = (TJ-Tamb)/RthJA = (150-90)/72.5 = 827.58mW . So the value given in design report is exceeding 827.58 mW . Can you please clear this doubt on what value of Thermal resistance you have calculated this value. & Also if you give the information regarding Layer of board & copper area for the thermal resistance it would be helpful. Please refer image from design report.