Thermal resistance, Heatsink design example – Philips TDA2613 User Manual

Page 5

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July 1994

5

Philips Semiconductors

Product specification

6 W hi-fi audio power amplifier

TDA2613

THERMAL RESISTANCE

HEATSINK DESIGN EXAMPLE

With derating of 8 K/W, the value of heatsink thermal resistance is calculated as follows:
given R

L

= 8

and V

P

= 24 V, the measured maximum dissipation is 4,1 W; then, for a maximum ambient temperature

of 60

°

C, the required thermal resistance of the heatsink is:

Note: The metal tab (heatsink) has the same potential as pin 5 (GND).

From junction to case

R

th j-c

= 8 K/W

Fig.2 Power derating curve.

R

th h-a

150

60

4 1

,

----------------------

8

14 K/W

=

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