TDA7491LP13TR STMicroelectronics, TDA7491LP13TR Datasheet - Page 32

• Manufacturer Part Number: TDA7491LP13TR
• Description: IC AMP AUD CLASS D BTL PWRSSO36
• Manufacturer: STMicroelectronics
• Type: Class Dr

Specifications of TDA7491LP13TR

• Output Type: 2-Channel
• Max Output Power X Channels @ Load: 5W x 2 @ 8 Ohm
• Voltage - Supply: 5 V ~ 14 V
• Features: Depop, Differential Inputs, Mute, Short-Circuit and Thermal Protection, Standby
• Mounting Type: Surface Mount
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-11056-2

Applications information
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Heatsink requirements
Due to the high efficiency of the class-D amplifier a 2-layer PCB can easily provide the
heatsinking capability for low to medium power outputs.
Using such a PCB with a copper ground layer of 3 x 3 cm
contact area for the exposed pad, a thermal resistance, junction to ambient (in natural air
convection), of 24 °C/W can be achieved.
The dissipated power within the device depends primarily on the supply voltage, load
impedance and output modulation level. With the TDA7491LP driving 2 x8 Ω with a supply
of 9 V then the maximum device dissipation is approximately 1 W.
When this power is dissipated at the maximum ambient temperature of 85 °C and the device
is mounted on the above PCB then the junction temperature could reach:
However, this temperature is sufficiently low to avoid triggering thermal warning.
With a musical program the dissipated power is about 40% less than the above maximum
value. This leads to a junction temperature of around only 99 °C with the 9 cm2 copper
ground. A commensurately smaller heatsink can thus be used.
Figure 36
copper areas of 2 x 2 cm
Figure 36. Power derating curves for PCB used as heatsink
Pd (W)
Tj = Tamb + Pd * Rj-amb = 85 + 1 * 24 = 109 °C
shows the power derating curve for the PowerSSO-36 package on PCBs with
8
7
6
5
4
3
2
1
0
0
Copper Area 2x2 cm
and via holes
2
20
and 3 x 3 cm
Doc ID 13541 Rev 5
Copper Area 3x3 cm
and via holes
40
2
.
60
Tamb ( °C)
80
g
2
100
and 16 vias connecting it to the
TDA7491P
PSSO36
TDA7491LP
PowerSSO-36
120
140
TDA7491LP
160