A

J

JA D max

T Max

T Max

P

150

24(1.5)

114 C

=

- q

=

-

=

°

JA

1

1

24 C / W

Derating Factor

0.041

q

=

=

=

°

23

TPA2012D2

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SLOS438F – DECEMBER 2004 – REVISED MARCH 2017

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12.3 Efficiency and Thermal Considerations

The maximum ambient temperature depends on the heat-sinking ability of the PCB system. The derating factor

Equation 3.

(3)

dissipation of 1.5 W (0.75 W per channel) for 2.1 W per channel, 4-Ω load, 5-V supply, from Figure 25, the

maximum ambient temperature can be calculated with Equation 4.

(4)

Equation 4 shows that the calculated maximum ambient temperature is 114°C at maximum power dissipation

with a 5-V supply and a 4-Ω load. The TPA2012D2 is designed with thermal protection that turns the device off

when the junction temperature surpasses 150°C to prevent damage to the IC. Also, using speakers more

resistive than 4-Ω dramatically increases the thermal performance by reducing the output current and increasing

the efficiency of the amplifier.