Datasheet
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APPLICATION SCHEMATICS
Audio
Input
Bias
Control
V
DD
350 mW
6
5
7
V
O
+
V
DD
1
2
4
BYPASS
IN -
V
DD
/2
C
S
1
µ
F
C
B
2.2
µ
F
SHUTDOWN
V
O
- 8
GND
From System Control
3 IN+
-
+
-
+
C
I
0.47 µF
R
I
10 kΩ
R
F
50 kΩ
C
F
5 pF
Audio
Input-
Bias
Control
V
DD
700 mW
6
5
7
V
O
+
V
DD
1
2
4
BYPASS
IN -
V
DD
/2
C
I
C
S
1
µ
F
C
B
2.2
µ
F
SHUTDOWN
V
O
- 8
GND
From System Control
3 IN+
R
I
10 kΩ
R
F
50 kΩ
-
+
-
+
R
I
10 kΩ
Audio
Input+
C
I
R
F
50 kΩ
TPA321
SLOS312C – JUNE 2000 – REVISED JUNE 2004
Figure 26 is a schematic diagram of a typical handheld audio application circuit, configured for a gain of –10 V/V.
Figure 26. TPA321 Application Circuit
Figure 27 is a schematic diagram of a typical handheld audio application circuit, configured for a gain of –10 V/V
with a differential input.
Figure 27. TPA321 Application Circuit With Differential Input
It is important to note that using the additional R
F
resistor connected between IN+ and BYPASS causes V
DD
/2 to
shift slightly, which could influence the THD+N performance of the amplifier. Although an additional external
operational amplifier could be used to buffer BYPASS from R
F
, tests in the lab have shown that the THD+N
performance is only minimally affected by operating in the fully differential mode as shown in Figure 27 . The
following sections discuss the selection of the components used in Figure 26 and Figure 27 .
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