Heatsink Requirements - Philips TDA8950 Product Data Sheet

NXP Semiconductors

13.5 Heatsink requirements

TDA8950_2
Product data sheet
An external heatsink must be connected to the TDA8950.
Equation 5 defines the relationship between maximum power dissipation before activation
of TFB and total thermal resistance from junction to ambient.
T – T
j amb
R = ----------------------- -
th j a –
P
Power dissipation (P) is determined by the efficiency of the TDA8950. Efficiency
measured as a function of output power is given in
derived as a function of output power as shown in
(1) R = 5 K/W.
th(j-a)
(2) R = 10 K/W.
th(j-a)
(3) R = 15 K/W.
th(j-a)
(4) R = 20 K/W.
th(j-a)
(5) R = 35 K/W.
th(j-a)
Fig 9. Derating curves for power dissipation as a function of maximum ambient
temperature
30
P
(W)
(1)
20
(2)
10
(3)
(4)
(5)
0
0 20 40
Rev. 02 — 11 June 2009
2 150 W class-D power amplifier
Figure 20. Power dissipation can be
Figure 19.
mbl469
60 80 100
T ( C)
amb
TDA8950
(5)
© NXP B.V. 2009. All rights reserved.
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