TDA7266SA Datasheet, PDF (8/11 Pages) STMicroelectronics – 7W+7W DUAL BRIDGE AMPLIFIER

TDA7266SA
HEAT SINK DIMENSIONING:
In order to avoid the thermal protection intervention, that is placed approximatively at T_j = 150°C, it is important
the dimensioning of the Heat Sinker R_Th (°C/W).
The parameters that influence the dimensioning are:
– Maximum dissipated power for the device (P_dmax)
– Max thermal resistance Junction to case (R_{Th j-c})
– Max. ambient temperature T_{amb max}
– Quiescent current I_q (mA)
Example:
V_CC = 11V, R_load = 8ohm, R_{Th j-c} = 2.5 °C/W , T_{amb max} = 50°C
P_dmax
=
(N°
channels)
·
--------^V----^c---^c---²--------
Π²
⋅
-^R----^l-^o---^a----^d-
2
+
I_q
⋅
V_cc
P_dmax = 2 · ( 3.0 ) + 0.5 = 6.5 W
(Heat Sinker)
R_{Th c-a}
=
1_----5_---0_{-----–-----}T_{---a---m-----b----m----a---x-}
P_{d max}
–
R_Th
j-c
=
-¹---⁵---⁰-----–----⁵----⁰-- – 2.5
6.5
=
12.8 ° C /W
In figure 12 is shown the Power derating curve for the device.
Figure 12. Power derating curve
25
20
(a)
15
(b)
10
(c)
5
a) Infinite Heatsink
b) 7 °C/ W
c) 10 °C/ W
0
0
40
80
120
160
Tamb (°C)
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