July 1994
5
Philips Semiconductors
Product specification
2 x 6 W hi-fi audio power amplifier
TDA1521A
THERMAL RESISTANCE
HEATSINK DESIGN EXAMPLE
With derating of 6 K/W, the value of heatsink thermal resistance is calculated as follows:
given R
L
= 8
Ω
and V
P
=
±
12 V, the measured maximum dissipation is 7,8 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 (
−
V
P
).
From junction to case
R
th j-c
= 6 K/W
Fig.2 Power derating curve.
R
th h-a
150
60
–
7 8
,
----------------------
6
5,5 K/W
=
–
=
