Datasheet

TPA0202
2-W STEREO AUDIO POWER AMPLIFIER
SLOS205B – FEBRUARY 1998 – REVISED DECEMBER 2000
34
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
output coupling capacitor, C
C
In the typical single-supply SE configuration, an output coupling capacitor (C
C
) is required to block the dc bias
at the output of the amplifier thus preventing dc currents in the load. As with the input coupling capacitor, the
output coupling capacitor and impedance of the load form a high-pass filter governed by equation 14.
(14)
f
c(high)
1
2 R
L
C
C
–3 dB
f
c
The main disadvantage, from a performance standpoint, is the load impedances are typically small, which drives
the low-frequency corner higher degrading the bass response. Large values of C
C
are required to pass low
frequencies into the load. Consider the example where a C
C
of 330 µF is chosen and loads vary from 3 Ω,
4 Ω, 8 Ω, 32 Ω, 10 kΩ, to 47 kΩ. Table 2 summarizes the frequency response characteristics of each
configuration.
Table 2. Common Load Impedances Vs Low Frequency Output Characteristics in SE Mode
R
L
C
C
LOWEST FREQUENCY
3 Ω 330 µF 161 Hz
4 Ω 330 µF 120 Hz
8 Ω 330 µF 60 Hz
32 Ω 330 µF
15 Hz
10,000 Ω 330 µF 0.05 Hz
47,000 Ω 330 µF 0.01 Hz
As Table 2 indicates, most of the bass response is attenuated into a 4-Ω load, an 8-Ω load is adequate,
headphone response is good, and drive into line level inputs (a home stereo for example) is exceptional.