TDA7253L Datasheet, PDF (5/8 Pages) STMicroelectronics – 6W AMPLIFIER WITH MUTING

TDA7253L
3 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)
3.1 Example:
V_CC = 20V, R_load = 8ohm, R_{Th j-c} = 9 °C/W , T_{amb max} = 50°C
P_dmax = (N° channels) · _Π------₂²----^V_â‹---_R-^c---^cl--_o2---_a---_d- + I_q ⋅ V_cc
P_dmax = 1 · ( 2.5 ) + 0.5 = 3W
(Heat Sinker) R_{Th c-a} = ¹----⁵---⁰-----–_P-----_d^T----^am---^m-_a---_xb-----^m----^a--^x- – R_{Th j-c} = ¹----⁵---⁰---₆--–-----⁵---⁰-- – 9 = 24.3°C /W
In figure 8 is shown the Power derating curve for the device.
Figure 11. Power Derating Curve
10
8
6
(c)
4
(d)
2
0
0
40
(a)
(b)
80
120
Tamb (°C)
a) Infinite Heatsink
b) 10 °C/ W
c) 15 °C/ W
d) 20 °C/ W
160
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