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TDA7297SA Datasheet, PDF (8/11 Pages) STMicroelectronics – 10W+10W DUAL BRIDGE AMPLIFIER | |||
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TDA7297SA
HEAT SINK DIMENSIONING:
In order to avoid the thermal protection intervention, that is placed approximatively at Tj = 150°C, it is important
the dimensioning of the Heat Sinker RTh (°C/W).
The parameters that influence the dimensioning are:
â Maximum dissipated power for the device (Pdmax)
â Max thermal resistance Junction to case (RTh j-c)
â Max. ambient temperature Tamb max
â Quiescent current Iq (mA)
Example:
VCC = 13V, Rload = 8ohm, RTh j-c = 2.5 °C/W , Tamb max = 50°C
Pdmax
=
(N°
channels)
·
--------V----c---c---2--------
Î 2
â
-R----l-o---a----d-
2
+
Iq
â
Vcc
Pdmax = 2 · ( 4.28 ) + 0.5 = 9 W
(Heat Sinker)
RTh c-a
=
1----5---0-----â-----T---a---m-----b----m----a---x-
Pd max
â
RTh
j-c
=
1----5---0-----â----5----0-- â 2.5
9
=
8.6 ° C /W
In figure 15 is shown the Power derating curve for the device.
Figure 15. Power derating curve
35
30
25
20
15
10
5
0
0
(a)
(c)
(b)
(d)
a) Infinite Heatsink
b) 3.5 °C/ W
c) 5.0 °C/ W
d) 7.0 °C/ W
40
80
120
160
Tamb (°C)
8/11
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