ZHCSH72I September 2011 – December 2017 LMK00301
This example shows how to calculate IC power dissipation for a configuration to estimate worst-case power dissipation. In this case, the maximum supply voltage and supply current values specified in Electrical Characteristics are used.
Using the maximum supply current and power calculations from the previous section, we can compute PTOTAL and PDEVICE.
In this worst-case example, the IC device will dissipate about 992.4 mW or 60% of the total power (1642.4 mW), while the remaining 40% will be dissipated in the LVPECL emitter resistors (255 mW for 10 pairs) and termination voltage (395 mW into Vcco - 2 V).
Based on θJA of 28.5 °C/W, the estimated die junction temperature would be about 28.3 °C above ambient, or 113.3 °C when TA = 85 °C.