TPA721

700-mW MONO LOW-VOLTAGE AUDIO POWER AMPLIFIER

SLOS231B – NOVEMBER 1998 – REVISED MARCH 2000

19

POST OFFICE BOX 655303

APPLICATION INFORMATION

headroom and thermal considerations (continued)

This is valuable information to consider when attempting to estimate the heat dissipation requirements for the

amplifier system. Comparing the absolute worst case, which is 700 mW of continuous power output with 0 dB

of headroom, against 12 dB and 15 dB applications drastically affects maximum ambient temperature ratings

for the system. Using the power dissipation curves for a 5-V, 8-

Ω system, the internal dissipation in the TPA721

and maximum ambient temperatures is shown in Table 2.

Table 2. TPA721 Power Rating, 5-V, 8-

Ω, BTL

PEAK OUTPUT

AVERAGE OUTPUT

POWER

D PACKAGE

(SOIC)

DGN PACKAGE

(MSOP)

POWER

(mW)

AVERAGE OUTPUT

POWER

DISSIPATION

(mW)

MAXIMUM AMBIENT

TEMPERATURE

(0 CFM)

MAXIMUM AMBIENT

TEMPERATURE

(0 CFM)

700

700 mW

675

34

°C

110

°C

700

350 mW (3 dB)

595

47

°C

115

°C

700

176 mW (6 dB)

475

68

°C

122

°C

700

88 mW (9 dB)

350

89

°C

125

°C

700

44 mW (12 dB)

225

111

°C

125

°C

Table 2 shows that the TPA721 can be used to its full 700-mW rating without any heat sinking in still air up to

110

°C and 34°C for the DGN package (MSOP) and D pacakge (SOIC) respectively.