External Components Description
Components
1
R
B
Functional Description
Prevents currents from entering the amplifier’s non-inverting input which may be passed through to the
load upon power down of the system due to the low input impedance of the circuitry when the
undervoltage circuitry is off. This phenomenon occurs when the supply voltages are below 1.5V.
Inverting input resistance to provide AC gain in conjunction with R
f
.
Feedback resistance to provide AC gain in conjunction with R
i
.
Feedback capacitor which ensures unity gain at DC. Also creates a highpass filter with R
i
at f
C
=
1/(2πR
i
C
i
).
Provides power supply filtering and bypassing. Refer to the Supply Bypassing application section for
proper placement and selection of bypass capacitors.
Acts as a volume control by setting the input voltage level.
Sets the amplifier’s input terminals DC bias point when C
IN
is present in the circuit. Also works with C
IN
to
create a highpass filter at f
C
= 1/(2πR
IN
C
IN
). Refer to
Figure 4.
Input capacitor which blocks the input signal’s DC offsets from being passed onto the amplifier’s inputs.
Works with C
SN
to stabilize the output stage by creating a pole that reduces high frequency instabilities.
Works with R
SN
to stabilize the output stage by creating a pole that reduces high frequency instabilities.
The pole is set at f
C
= 1/(2πR
SN
C
SN
). Refer to
Figure 4.
Provides high impedance at high frequencies so that R may decouple a highly capacitive load and reduce
the Q of the series resonant circuit. Also provides a low impedance at low frequencies to short out R and
pass audio signals to the load. Refer to
Figure 4.
Provides DC voltage biasing for the transistor Q1 in single supply operation.
Provides bias filtering for single supply operation.
Limits the voltage difference between the amplifier’s inputs for single supply operation. Refer to the
Clicks
and Pops
application section for a more detailed explanation of the function of R
INP
.
Provides input bias current for single supply operation. Refer to the
Clicks and Pops
application section
for a more detailed explanation of the function of R
BI
.
Establishes a fixed DC current for the transistor Q1 in single supply operation. This resistor stabilizes the
half-supply point along with C
A
.
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
R
i
R
f
C
i
(Note 14)
C
S
R
V
(Note 14)
R
IN
(Note 14)
C
IN
(Note 14)
R
SN
(Note 14)
C
SN
(Note 14)
L (Note 14)
R (Note 14)
R
A
C
A
R
INP
(Note 14)
R
BI
R
E
Note 14:
Optional components dependent upon specific design requirements.
Typical Performance Characteristics
THD + N vs Frequency
THD + N vs Frequency
THD + N vs Frequency
DS012072-13
DS012072-14
DS012072-15
7
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