clc427 National Semiconductor Corporation, clc427 Datasheet - Page 4

• Manufacturer Part Number: clc427
• Description: Dual Voltage Feedback Amplifier For Single Supply Operation
• Manufacturer: National Semiconductor Corporation

Description
The CLC427 contains two single supply voltage-feed-
back amplifiers. The CLC427 is a dual version of the
CLC423 with the following features:
Single Supply Operation (V
The CLC427 is designed to operate from 0 and 5V
supplies. The specifications given in the Electrical
Characteristics table are measured with a common
mode voltage (V
which the inputs are applied and the output voltages are
specified.
Operating from a single +5V supply, the CMIR of the
CLC427 is typically 0V to +3.7V. The typical output range
with R
For simple single supply operation, it is recommended
that input signal levels remain above ground. For input
signals that drop below ground, AC coupling and level
shifting the signal are possible remedies.
signals that remain above ground, no adjustments need
to
configurations for both input conditions are illustrated in
the following 2 sections.
Standard Single Supply Operation
Figures 1 and 2 show the recommended non-inverting
and inverting configurations for purely positive input
signals.
http://www.national.com
V
be
• Operates from a single +5V supply
• Maintains near rail-to-rail performance
• Includes the negative rail (0V) in the Common
• Offers low -74/-94dBc 2nd and 3rd harmonic
• Provides BW > 20MHz and 1MHz distortion
in
L
Mode Input Range (CMIR)
distortion
< -50dBc at V
= 150
Figure 1: Non-inverting Configuration
made.
R
is +0.35V to +4.5V.
t
cm
The
) of 2.5V. V
3(5)
2(6)
R
o
g
= 4V
CLC427
non-inverting
+
-
+5V
1/2
pp
8
4
CC
6.8 F
0.1 F
cm
= +5V, V
+
R
V
V
f
in
is the voltage around
1(7)
o
1
CLC427 OPERATIONS
R
EE
and
R
g
f
= GND)
V
o
For input
inverting
4
Single Supply Operation for Inputs that go below 0V
Figures 3 and 4 show possible non-inverting and invert-
ing configurations for input signals that go below ground.
The input is AC coupled to prevent the need for level
shifting the input signal at the source. The resistive volt-
age divider biases the non-inverting input to V
2.5V.
Figure 3: AC Coupled Non-inverting Configuration
low frequency cutoff
V
R >> R
o
low frequency cutoff
V
Figure 4: AC Coupled Inverting Configuration
o
V
V
in
V
V
in
in
in
source
V
1
Figure 2: Inverting Configuration
C
in
R
R
c
g
f
R
R
R
g
f
t
2.5V
2.5
R
2.5V
R
R
2.5
C
b
g
g
c
2 R C
2 R C
V
V
3(5)
2(6)
in
o
1
1
g c
in c
R
R
R
R
CLC427
+
-
+5V
R
R
, where: R
1/2
g
f
8
4
3(5)
2(6)
3(5)
2(6)
R
C
6.8 F
0.1 F
g
Select R to yield
desired R
+
R
CLC427
CLC427
+
-
+
-
+5V
f
1(7)
in
+5V
1/2
1/2
8
4
4
8
R
2
6.8 F
0.1 F
t
6.8 F
0.1 F
in
+
R
+
R
f
1(7)
f
1(7)
R || R
V
R C
t
o
g
CC
g
RC
V
÷ 2 =
o
c
V
o