TPA3002D2

SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004

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Example. What is the maximum ambient temperature for an application that requires the TPA3002D2 to drive

7.5 W into stereo 8-

Ω speakers?

99.65

°C

This calculation shows that the TPA3002D2 can drive 7.5 W into an 8-

Ω speaker up to the absolute maximum

ambient temperature rating of 85

°C, which must never be exceeded.

Figure 38 and Figure 39 show the results of several thermal experiments conducted with the TPA3002D2. Both

figures show that the best thermal performance can be achieved with more copper area for heat dissipation

and an adequate number of thermal vias.

Figure 38 shows two curves for a 2-layer and 4-layer PCB. The 2-layer PCB layout was tightly controlled with

a fixed amount of 2 oz. copper on the bottom layer of the PCB. The amount of copper is shown on the x-axis.

Nine thermal vias of 13 mil (0,33 mm) diameter were drilled under the PowerPad and connected to the bottom

layer. The top layer only consisted of traces for signal routing.

The 4-layer PCB layout was also tightly controlled with a fixed amount of 2 oz. copper in middle GND layer. The

top layer only consisted of traces for signal routing. The bottom and other middle layer were left blank. Nine

thermal vias of 0,33 mm diameter were drilled under the PowerPAD and connected to the middle layer.

Figure 39 shows the effect of the number of thermal vias drilled under the PowerPAD on the thermal

performance of the PCB. The experiment was conducted with a 2-layer PCB and 3 square inches of copper

on the bottom layer. For the best thermal performance, at least 16 vias in a 4x4 pattern should be used under

the PowerPAD. Refer to the TPA3002D2 EVM User’s Manual (SLOU151), for an example layout with a 4x4

via pattern. PCB gerber files are available at request.