TDA7266SAN Datasheet, PDF (11/15 Pages) STMicroelectronics – 5 W + 5 W dual bridge amplifier

TDA7266SAN
7
Heatsink dimensioning
Heatsink dimensioning
In order to avoid triggering the thermal protection which is set approximatively at T_j = 150°C,
it is important to correctly dimension 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 = 9.5 V, R_load = 8 ohm, R_{Th j-c} = 2.5 °C/W , T_{amb max} = 50 °C
P_dmax
=
(N^ochannels)
•
-------^V-----^C---^C----²--------
Π²
•
-^R----^l-^o---^a---^d-
2
+
I_q
•
V_CC
P_dmax = 2 • (2.3) + 0.47= 5.07W
(HeatSinker)R_Th
c–a
=
1_----5_---0_{-----–-----}T_{---a---m-----b-----m----a---x-}
P_dmax
–
R_Th
j – c⁼
⎛
⎝
1_----5_---0_{-----–-----}5_---0_--
5.07
–
2.5_⎠⎞
=
17.2^oC/W
Figure 14 shows the power derating curve for the device.
Figure 14. 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)
Doc ID 023621 Rev 1
11/15