APA2065JI-TRL 查看數據表（PDF） - Anpec Electronics

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APA2065JI-TRL

Stereo 2.7-W Audio Power Amplifier (with DC_Volume Control)

Anpec Electronics 

APA2065

Application Descriptions (Cont.)

BTL Amplifier Efficiency (Cont.)

denominator. This indicates that as V goes down,

DD

efficiency goes up. In other words, use the efficiency

analysis to choose the correct supply voltage and

speaker impedance for the application.

assuming a 5V-power supply and an 8Ω load, must

not be greater than the power dissipation that results

from the equation15:

PD,MAX=

TJ,MAX -

θJA

TA

(15)

Po (W) Efficiency (%) IDD(A) VPP(V) PD (W)

0.25

31.25

0.16 2.00 0.55

0.50

47.62

0.21 2.83 0.55

1.00

66.67

0.30 4.00 0.5

1.25

78.13

0.32 4.47 0.35

**High peak voltages cause the THD to increase.

Table 1. Efficiency Vs Output Power in 5-V/8Ω BTL

Systems

Power Dissipation

For DIP-16 package with thermal pad, the thermal

resistance (θJA) is equal to 45οC/W.

Since the maximum junction temperature (TJ,MAX) of

APA2065 is 150οC and the ambient temperature (T )

A

is defined by the power system design, the maximum

power dissipation which the IC package is able to

handle can be obtained from equation15.

Once the power dissipation is greater than the

maximum limit (PD,MAX), either the supply voltage

(VDD) must be decreased, the load impedance (RL)

must be increased or the ambient temperature

should be reduced.

Whether the power amplifier is operated in BTL or SE

modes, power dissipation is a major concern. In

equation13 states the maximum power dissipation

point for a SE mode operating at a given supply

voltage and driving a specified load.

SE

mode

:

PD,MAX=

VDD2

2π 2RL

(13)

In BTL mode operation, the output voltage swing is

doubled as in SE mode. Thus the maximum power

dissipation point for a BTL mode operating at the same

given conditions is 4 times as in SE mode.

BTL

mode

:

PD,MAX=

4VDD2

2π 2RL

(14)

Since the APA2065 is a dual channel power amplifier,

the maximum internal power dissipation is 2 times

that both of equations depending on the mode of

operation. Even with this substantial increase in power

dissipation, the APA2065 does not require extra

heatsink. The power dissipation from equation14,

Copyright © ANPEC Electronics Corp.

20

Rev. A.4 - Aug., 2005

www.anpec.com.tw

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