resistance, junction - case Thermal resistance, junction - ambient (PCB mount)** Thermal resistance, junction - ambient IEC climatic category, DIN IEC 68-1 Tj Tstg RthJC RthJA RthJA -55 ... + 175 -55 ... + 175 °C ≤ 2.7 ≤ 50 ≤ 100 55 / 175 / 56 K/W ** when mounted on 1 " square PCB ( FR4 );for.