TDA7499SA Datasheet, PDF (7/11 Pages) STMicroelectronics – 6W+6W STEREO AMPLIFIER WITH MUTE & ST-B

TDA7499SA
6 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 = ±10V, R_load = 8ohm, R_{Th j-c} = 3.9 °C/W , T_{amb max} = 50°C
P_dmax = (N° channels) · -_Π----₂-²----_â‹^V---_R-^c---^cl--_o2---_a---_d- + I_q ⋅ V_cc
P_dmax = 2 · ( 2.5 ) + 0.8 = 6W
(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-- – 3.9 = 12.7°C/W
In figure 7 is shown the Power derating curve for the device.
Figure 10. Power Derating Curve
25
20
15
10
5
0
0
(a)
(b)
(c)
40
80
120
Tamb (°C)
a) Infinite Heatsink
b) 10 °C/ W
c) 15 °C/ W
160
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