Question

A power transistor with an area A of 1 mm^2 dissipates 10 watts. It is attached to a heat sink 2 mm thick, effectively cooled to 30°C on the back face by forced airflow. If the heat sink is made of aluminum nitride, approximately how hot will the microchip be at steady state? Thermal conductivity of aluminum nitride is 140–180 W/mK.

Answer 1

Answer:

the microchip temperature will be 155° C

Explanation:

Area of the power transistor A= 1mm^2

A=  10^(-6) m^2

thickness t= 2 mm

T_2= 30° C

K= 140-180 W/mk

K= (140+180)/2

K= 160 W/mK

W= 10 watts

to find T_1

we know that

W= KAΔT/t

value

putting

$10= 160\times10^{-6}\frac{T_1-30}{2\times10^{-3}}$

on solving we get T_1= 155° C

the microchip temperature will be 155° C