TPA102

150-mW STEREO AUDIO POWER AMPLIFIER

SLOS213C – AUGUST 1998 – REVISED MARCH 2000

21

POST OFFICE BOX 655303

APPLICATION INFORMATION

Table 1. Common Load Impedances Vs Low Frequency Output Characteristics in SE Mode

RL

CC

Lowest Frequency

32

Ω

68

µF

73 Hz

10,000

Ω

68

µF

0.23 Hz

47,000

Ω

68

µF

0.05 Hz

As Table 1 indicates, headphone response is adequate and drive into line level inputs (a home stereo for

example) is very good.

The output coupling capacitor required in single-supply SE mode also places additional constraints on the

selection of other components in the amplifier circuit. With the rules described earlier still valid, add the following

relationship:

(8)

1

C

B

160 k

Ω

v

1

C

1

R

using low-ESR capacitors

Low-ESR capacitors are recommended throughout this application. A real capacitor can be modeled simply as

a resistor in series with an ideal capacitor. The voltage drop across this resistor minimizes the beneficial effects

of the capacitor in the circuit. The lower the equivalent value of this resistance, the more the real capacitor

behaves like an ideal capacitor.

5-V versus 3.3-V operation

The TPA102 was designed for operation over a supply range of 2.5 V to 5.5 V. This data sheet provides full

specifications for 5-V and 3.3-V operation since these are considered to be the two most common standard

voltages. There are no special considerations for 3.3-V versus 5-V operation as far as supply bypassing, gain

setting, or stability. Supply current is slightly reduced from 3.5 mA (typical) to 2.5 mA (typical). The most

important consideration is that of output power. Each amplifier in the TPA102 can produce a maximum voltage

power into the load before distortion begins to become significant.