
External Components
(Figure 1)
Component
Typical Value
Comments
C
IN
1
m
F
Input coupling capacitor sets a low frequency pole with R
IN
.
1
2
q
R
IN
C
IN
f
L
e
R
IN
100k
Sets input impedance and DC bias to input.
R
f2
100k
Feedback resistor; for minimum offset voltage at the output this should be equal to R
IN
.
R
f1
5.1k
Feedback resistor that works with R
f2
to set the voltage gain.
A
V
e
1
a
R
f2
R
f1
C
f
10
m
F
Feedback capacitor. This reduces the gain to unity at DC for minimum offset voltage at the
output. Also sets a low frequency pole with R
f1
.
1
2
q
R
f1
C
f
f
L
e
C
C
5 pF
Compensation capacitor. Sets gain bandwidth product and a high frequency pole.
1
2
q
5000C
C
A
V
Max f
h
for stable design
&
500 kHz.
GBW
e
, f
h
e
GBW
R
A
3.9k
AB bias resistor.
R
B
10k
AB bias potentiometer. Adjust to set bias current in the output stage.
C
AB
0.1
m
F
Bypass capacitor for bias. This improves high frequency distortion and transient response.
C
R
5 pF
Ripple capacitor. This improves negative supply rejection at midband and high frequencies.
C
R
, if used, must equal C
C
.
R
eb
100
X
Bleed resistor. This removes stored charge in output transistors.
R
O
2.7
X
Output compensation resistor. This resistor and C
O
compensate the output stage. This value
will vary slightly for different output devices.
C
O
0.1
m
F
Output compensation capacitor. This works with R
O
to form a zero that cancels f
b
of the
output power transistors.
R
E
0.3
X
Emitter degeneration resistor. This resistor gives thermal stability to the output stage
quiescent current. IRC PW5 type.
R
TH
C
2
, C
ê
2
39k
Shutdown resistor. Sets the amount of current pulled out of pin 14 during shutdown.
1000 pF
Compensation capacitors for protection circuitry.
X
L
10
X
ll
5
m
H
Used to isolate capacitive loads, usually 20 turns of wire wrapped around a 10
X
, 2W resistor.
4