Philips Semiconductors
Product specification
5 W audio power amplifier
TDA2611A
Fig.2 Power derating curves.
HEATSINK EXAMPLE
Assume V = 18 V; R = 8 Ω; T
= 60 °C maximum; T = 150 °C (max. for a 4 W application into an 8 Ω load, the
j
P
L
amb
maximum dissipation is about 2,2 W).
The thermal resistance from junction to ambient can be expressed as:
150 – 60
Rth j-a = Rth j-tab + Rth tab-h + Rth h-a
=
= 41 K/W.
----------------------
2, 2
Since R
= 11 K/W and R
= 1 K/W, R = 41 − (11 + 1) = 29 K/W.
th h-a
th j-tab
th tab-h
November 1982
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