Features
s
Single +5V supply
s
Input includes V
EE
s
94MHz unity-gain bandwidth
s
-74/-94dBc HD2/HD3
s
60mA output current
s
7.5ns rise/fall time (1V
pp
)
s
46ns settling time to 0.1%
Applications
s
Video ADC driver
s
Desktop multimedia
s
Single supply cable driver
s
Instrumentation
s
Video cards
s
Wireless IF amplifiers
s
Telecommunications
General Description
The Comlinear CLC427 is a dual wideband voltage-feedback
operational amplifier that is uniquely designed to provide high
performance from a single power supply. This CLC427 provides
near rail-to-rail operation and the common-mode input range
includes the negative rail. Each of the CLC427's amplifiers offers
plenty of headroom for single-supply applications as evidenced
by its 4.3V
pp
output voltage from a single 5V supply.
Fabricated with a high-speed complementary bipolar process,
the CLC427 delivers a wide 94MHz unity-gain bandwidth, 7.5ns
rise/fall time and 150V/
s slew rate. For single supply applications
such as video distribution or desktop multimedia, the CLC427
offers low 0.35%, 0.55 differential gain and phase errors.
Each of the CLC427's amplifiers provides high signal fidelity
with -74/-94dBc 2nd/3rd harmonics (1V
pp
, 1MHz, R
L
=150
).
Combining this high fidelity performance with CLC427's quick
46ns settling time to 0.1% makes it an excellent choice for ADC
buffering.
With its traditional voltage-feedback architecture and high-speed
performance, the CLC427 is the perfect choice for composite
signal conditioning circuit functions such as active filters,
integrators, differentiators, simple gain blocks and buffering.
V
in
50
250
+
-
250
0.1
F
6.8
F
150
NOTE: V
in
= 0.15V to 2.3V
1/2
CLC427
V
o
+5V
+
Typical Application
Single +5V Supply operation
Comlinear CLC427
Dual Voltage Feedback Amplifier
for Single Supply Operation
Frequency Response vs. V
out
Magnitude (1dB/div)
Frequency (MHz)
1
10
100
1V
pp
2V
pp
4V
pp
A
v
= +2V/V
V
o1
V
inv1
V
non-inv1
V
EE
V
o2
V
inv2
V
non-inv2
V
CC
Pinout
DIP & SOIC
Single Supply Response
Output Voltage (V)
Time (100ns/div)
V
EE
0
1
2
3
4
V
CC
5
August 1996
Comlinear CLC427
Dual V
oltage Feedback
Amplifier for Single Supply Operation
N
1996 National Semiconductor Corporation
http://www.national.com
Printed in the U.S.A.
http://www.national.com
2
PARAMETERS
CONDITIONS
TYP
MIN/MAX RATINGS
UNITS
NOTES
CLC427AJ
25
25
0 to +70
-40 to +85
FREQUENCY DOMAIN RESPONSE
-3dB bandwidth
V
o
< 1.0V
pp
48
32
28
27
MHz
B
-3dB bandwidth
V
o
< 3.0V
pp
26
16
14
11
MHz
-3dB bandwidth A
V
= +1V/V
V
o
< 1.0V
pp
94
MHz
rolloff
<10MHz
0.1
0.5
0.7
0.8
dB
B
peaking
DC to 200MHz
0
0.5
0.7
0.8
dB
B
linear phase deviation
<15MHz
0.3
0.6
0.8
0.9
deg
differential gain
NTSC, R
L
=150
0.35
0.7
%
2
differential phase
NTSC, R
L
=150
0.55
2
deg
2
TIME DOMAIN RESPONSE
rise and fall time
1V step
7.5
13
14
16
ns
settling time to 0.1%
1V step
46
70
ns
overshoot
1V step
5
13
%
slew rate
A
V
= +2
2V step
150
90
83
65
V/
s
DISTORTION AND NOISE RESPONSE
2
nd
harmonic distortion
1V
pp
, 1MHz
74
-dBc
1V
pp
, 5MHz
62
55
52
52
-dBc
B
3
rd
harmonic distortion
1V
pp
, 1MHz
94
-dBc
1V
pp
, 5MHz
75
65
63
62
-dBc
B
equivalent input noise
voltage
>1MHz
10
12.5
13.6
14
nV/
Hz
current
>1MHz
4
5
5.5
5.7
pA/
Hz
crosstalk, input referred
10MHz
65
59
59
59
-dB
STATIC DC PERFORMANCE
input offset voltage
2
7
8
10
mV
A
average drift
4
22
35
V/C
input bias current
17
30
36
45
A
A
average drift
80
145
175
nA/C
input offset current
0.2
5
6
7.5
A
average drift
10
22
27
nA/C
power supply rejection ratio
DC
82
65
64
60
dB
B
common-mode rejection ratio
DC
82
55
53
50
dB
supply current (per amplifier)
no load
7
8.5
8.5
8.5
mA
A
MISCELLANEOUS PERFORMANCE
input capacitance
1
2
2
2
pF
input resistance
700
500
450
360
k
output impedance
@DC
0.07
0.15
0.24
0.7
input voltage range, high
3.7
3.45
3.25
3.15
V
input voltage range, low
0
0
0
0
V
output voltage range, high
R
L
= 150
4.5
4.35
4.3
4.2
V
output voltage range, low
R
L
= 150
0.35
0.5
0.5
0.55
V
output voltage range, high
no load
4.8
4.6
4.55
4.45
V
output voltage range, low
no load
0.45
0.65
0.7
0.75
V
output current
source
60
50
40
34
mA
output current
sink
36
20
16
10
mA
supply voltage, maximum
7
7
7
V
1
supply voltage, minimum
4
4
4
V
1
transistor count = 124
Min/max ratings are based on product characterization and simulation. Individual parameters are tested as noted. Outgoing quality levels are
determined from tested parameters.
Electrical Characteristics
(V
s
= +5V
1
, V
cm
= +2.5V, A
v
= +2, R
f
= 250
W,
R
L
= 150
W
to GND; unless specified)
Absolute Maximum Ratings
supply voltage (V
s
)
+7V
I
out
is short circuit protected to ground
common-mode input voltage
V
EE
to V
CC
maximum junction temperature
+175C
storage temperature range
-65C to +150C
lead temperature (soldering 10 sec)
+260C
differential input voltage
2V
ESD tolerance (Note 3)
2000V
Notes
A) J-level: spec is 100% tested at 25C, sample tested at 85C.
B) J-level: spec is sample tested at 25C.
1) V
s
= V
CC
V
EE
.
2) Tested with R
L
tied to +2.5V.
3) Human body model, 1.5k
in series with 100pF.
3
http://www.national.com
Typical Performance Characteristics
(V
s
= +5V
1
, V
cm
= +2.5V, A
v
= +2, R
f
= 250
W,
R
L
= 150
W
to GND; unless specified)
Non-Inverting Frequency Response
Magnitude (1dB/div)
Frequency (MHz)
1
10
100
A
v
= 1
R
f
= 0
Phase (deg)
-225
-180
-135
-90
-45
0
A
v
= 2
A
v
= 4
A
v
= 10
A
v
= 10
A
v
= 4
A
v
= 2
A
v
= 1
V
o
= 0.25V
pp
Inverting Frequency Response
Magnitude (1dB/div)
Frequency (MHz)
1
10
100
A
v
= -1
Phase (deg)
-45
0
45
90
135
180
A
v
= -2
A
v
= -5
A
v
= -10
A
v
= -10
A
v
= -5
A
v
= -2
A
v
= -1
V
o
= 0.25V
pp
Frequency Response vs. R
L
Magnitude (1dB/div)
Frequency (MHz)
0
10
100
R
L
= 1k
Phase (deg)
-225
-180
-135
-90
-45
0
45
90
135
180
225
R
L
= 150
R
L
= 75
R
L
= 75
R
L
= 150
R
L
= 1k
V
o
= 0.25V
pp
Frequency Response vs. V
out
Magnitude (1dB/div)
Frequency (MHz)
1
10
100
V
o
= 4V
pp
V
o
= 2V
pp
V
o
= 0.25V
pp
V
o
= 1V
pp
Frequency Response vs. C
L
Magnitude (1dB/div)
Frequency (MHz)
1
10
100
C
L
= 10pF
R
s
= 249
C
L
= 1000pF
R
s
= 22
C
L
= 100pF
R
s
= 54.9
1k
250
250
R
s
C
L
Open Loop Gain & Phase
Open Loop Gain (dB)
Frequency (MHz)
0.001
0.01
0.1
1
10
100
Phase (deg)
-120
Gain
-20
-100
0
-80
20
-60
40
-40
60
-20
80
0
100
Phase
Harmonic Distortion vs. Frequency
Distortion (dBc)
Frequency (MHz)
0.1
1
10
2nd
R
L
= 150
-100
-90
-80
-70
-60
-50
3rd
R
L
= 150
3rd
R
L
= 1k
2nd
R
L
= 1k
V
o
= 1V
pp
2nd Harmonic Distortion vs. V
out
Distortion (dBc)
Output Amplitude (V
pp
)
0
1
2
3
4
R
L
= 150
-80
-70
-60
-50
-40
-30
10MHz
5MHz
2MHz
1MHz
0.1MHz
-90
3rd Harmonic Distortion vs. V
out
Distortion (dBc)
Output Amplitude (V
pp
)
0
1
2
3
4
R
L
= 150
-80
-70
-60
-50
-40
-30
10MHz
5MHz
2MHz
1MHz
0.1MHz
-90
-100
Small Signal Pulse Response
Output Voltage (0.05V/div)
Time (20ns/div)
Large Signal Pulse Response
Output Voltage (0.5V/div)
Time (20ns/div)
Equivalent Input Noise
Voltage Noise (nV/Hz)
Frequency (MHz)
0.001
0.1
10
Current Noise (pA/Hz)
1
Voltage = 9.5nV/
Hz
1
10
10
100
100
1
0.01
Current = 3.2pA/
Hz
I
B
, V
IO
, vs. Temperature
V
IO
(mV)
Temperature (
C)
-40
-20
0
20
40
60
I
B
(
A)
-22
I
B
0.5
-20
0.7
-18
0.9
-16
1.1
-14
1.3
-12
1.5
-10
1.7
V
IO
80
Differential Gain and Phase (3.58MHz)
Gain (%)
Number of 150
Loads
1
2
3
4
Phase (deg)
0
0
0.5
0.5
1
1
1.5
1.5
2
2
2.5
2.5
Phase Neg Sync
Gain Neg Sync
R
L
tied to +2.5V
PSRR, CMRR & Linear R
out
vs. Frequency
PSRR, CMRR (dB)
Frequency (MHz)
0.001
0.01
0.1
1
Output Resistance (
)
0
0
5
20
10
40
15
60
20
80
25
100
10
PSRR
R
out
CMRR
http://www.national.com
4
CLC427 OPERATIONS
Description
The CLC427 contains two single supply voltage-feed-
back amplifiers. The CLC427 is a dual version of the
CLC423 with the following features:
Operates from a single +5V supply
Maintains near rail-to-rail performance
Includes the negative rail (0V) in the Common
Mode Input Range (CMIR)
Offers low -74/-94dBc 2nd and 3rd harmonic
distortion
Provides BW > 20MHz and 1MHz distortion
< -50dBc at V
o
= 4V
pp
Single Supply Operation (V
CC
= +5V, V
EE
= GND)
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
cm
) of 2.5V. V
cm
is the voltage around
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
L
= 150
is +0.35V to +4.5V.
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. For input
signals that remain above ground, no adjustments need
to be made. The non-inverting and inverting
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.
Figure 1: Non-inverting Configuration
Figure 2: Inverting Configuration
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
CC
2 =
2.5V.
Figure 3: AC Coupled Non-inverting Configuration
Figure 4: AC Coupled Inverting Configuration
+
-
1/2
CLC427
R
f
0.1
F
6.8
F
V
o
V
in
+5V
R
g
R
t
3(5)
2(6)
4
8
1(7)
V
V
1
R
R
o
in
f
g
= +
+
+
-
1/2
CLC427
R
f
0.1
F
6.8
F
V
o
V
in
+5V
R
b
3(5)
2(6)
4
8
1(7)
R
g
R
t
V
V
R
R
o
in
f
g
= -
Select R to yield
desired R
R || R
t
in
t
g
=
+
+
-
1/2
CLC427
R
f
0.1
F
6.8
F
V
o
V
in
+5V
R
g
R
3(5)
2(6)
4
8
1(7)
C
C
c
R
+
V
V
1
R
R
2.5
o
in
f
g
=
+
+
low frequency cutoff
1
2 R C
, where: R
R
2
in
c
in
=
=
2.5V
R C
RC
g
c
>>
+
-
1/2
CLC427
R
f
0.1
F
6.8
F
V
o
V
in
+5V
R
3(5)
2(6)
4
8
1(7)
C
c
R
+
V
V
R
R
2.5
o
in
f
g
=
-
+
low frequency cutoff
1
2 R C
g
c
=
2.5V
R
g
R >> R
source
5
http://www.national.com
Load Termination
Since the CLC427 design has been optimized for Single
Supply Operation, it is more capable of sourcing rather
than sinking current. For optimum performance, the load
should be tied to V
EE
. When the load is tied to V
EE
, the
output always sources current.
Output Overdrive Recovery
When the output range of an amplifier is exceeded, time
is required for the amplifier to recover from this over
driven condition. Figure 5 illustrates the overload
recovery of the CLC427 when the output is overdriven.
An input was applied in an attempt to drive the
output to twice the supply rails, V
CC
- V
EE
= 10V, but
the output limits. An inverting gain topology was used,
see Figure 2. As indicated, the CLC427 recovers within
25ns on the rising edge and within 10ns on the falling
edge.
Figure 5: Overdrive Recovery
Channel Matching
Channel matching and crosstalk rejection are largely
dependent on board layout. The layout of Comlinear's
dual amplifier evaluation boards are designed to produce
optimum channel matching and isolation. Channel
matching for the CLC427 is shown in Figure 6.
Figure 6: Channel Matching
The CLC427's channel-to-channel isolation is better than
-70dB for video frequencies of 4MHz. Input referred
crosstalk vs frequency is illustrated in Figure 7. Pulsed
crosstalk is shown in Figure 8.
Figure 7: Input Referred Crosstalk vs. Frequency
Figure 8: Pulsed crosstalk
Driving Cables and Capacitive Loads
When driving cables, double termination is used to
prevent reflections. For capacitive load applications, a
small series resistor at the output of the CLC427 will
improve stability. The
Frequency Response vs.
Capacitive Load
plot, in the typical performance
section, gives the recommended series resistance value
for optimum flatness at various capacitive loads.
Power Dissipation
The power dissipation of an amplifier can be described in
two conditions:
Quiescent Power Dissipation -
P
Q
(No Load Condition)
Total Power Dissipation -
P
T
(with Load Condition)
The following steps can be taken to determine the power
consumption for each CLC427 amplifier:
1. Determine the quiescent power
P
Q
= I
CC
(V
CC
V
EE
)
2. Determine the RMS power at the output stage
P
O
= (V
CC
V
load
) (I
load
)
3. Determine the total RMS power
P
T
= P
Q
+ P
O
Add the total RMS powers for both channels to determine
the power dissipated by the dual.
Input Voltage (4V/div)
Time (50ns/div)
Output Voltage (2V/div)
Input
Output
Magnitude (0.5dB/div)
Frequency (MHz)
Channel A
Channel B
V
out
= 0.25V
pp
1
10
Crosstalk (dB)
Frequency (MHz)
1
10
100
-100
-90
-80
-70
-60
-50
-40
Output Channel A (1V/div)
Time (50ns/div)
Output Channel B (20mV/div)
Channel A
Channel B
PDF 
ZIP