TPA032D02

10-W STEREO CLASS-D AUDIO POWER AMPLIFIER

SLOS243A – DECEMBER 1999 – REVISED MARCH 2000

20

POST OFFICE BOX 655303

APPLICATION INFORMATION

crest factor and thermal considerations (continued)

Table 3. TPA032D02 Power Rating, 12-V, 4-

Ω, Stereo

PEAK OUTPUT POWER

AVERAGE OUTPUT POWER

POWER DISSIPATION

MAXIMUM AMBIENT

(W)

AVERAGE OUTPUT POWER

(W/Channel)

TEMPERATURE

20

10 W (3 dB)

2.84

23

°C

20

5 W (6 dB)

1.66

75

°C

20

2.5 W (9 dB)

1.12

100

°C

20

1.25 W (12 dB)

0.87

111

°C

20

630 mW (15 dB)

0.7

118

°C

20

315 mW (18 dB)

0.6

123

°C

The maximum ambient temperature depends on the heatsinking ability of the PCB system. Using the 0 CFM

a multilayer PCB is 44.8 mW/

Θ

1

Derating

+

1

0.0448

(19)

To calculate maximum ambient temperatures, first consider that the numbers from the dissipation graphs are

per channel so the dissipated heat needs to be doubled for two channel operation. Given

allowable junction temperature, and the total internal dissipation, the maximum ambient temperature can be

calculated with the following equation. The maximum recommended junction temperature for the TPA032D02

is 150

°C. The internal dissipation figures are taken from the Efficiency vs Output Power graphs.

T

+ 150 * 22.3(0.7

2)

+ 150 * 22.3(2.84

2)

(20)

NOTE:

Internal dissipation of 1.4 W is estimated for a 10-W system with a 15 dB crest factor per channel.

The TPA032D02 is designed with thermal protection that turns the device off when the junction temperature

surpasses 150

°C to prevent damage to the IC. Table 3 was calculated for maximum listening volume without

distortion. When the output level is reduced the numbers in the table change significantly. Also, using 8-

Ω

speakers dramatically increases the thermal performance by increasing amplifier efficiency.