TL H 7845
LM387LM387A
Low
Noise
Dual
Preamplifier
March 1987
LM387 LM387A Low Noise Dual Preamplifier
General Description
The LM387 is a dual preamplifier for the amplification of low
level signals in applications requiring optimum noise per-
formance Each of the two amplifiers is completely indepen-
dent with an internal power supply decoupler-regulator pro-
viding 110 dB supply rejection and 60 dB channel separa-
tion Other outstanding features include high gain (104 dB)
large output voltage swing (V
CC
b
2V)p-p and wide power
bandwidth (75 kHz 20 Vp-p) The LM387A is a selected
version of the LM387 that has lower noise in a NAB tape
circuit and can operate on a larger supply voltage The
LM387 operates from a single supply across the wide range
of 9V to 30V the LM387A operates on a supply of 9V to
40V
The amplifiers are internally compensated for gains greater
than 10 The LN387 LM387A is available in an 8-lead dual-
in-line package The LM387 LM387A is biased like the
LM381 See AN-64 and AN-104
Features
Y
Low noise
1 0 mV total input noise
Y
High gain
104 dB open loop
Y
Single supply operation
Y
Wide supply range LM387
9 to 30V
LM387A
9 to 40V
Y
Power supply rejection
110 dB
Y
Large output voltage swing (V
CC
b
2V)p-p
Y
Wide bandwidth 15 MHz unity gain
Y
Power bandwidth 75 kHz 20 Vp-p
Y
Internally compensated
Y
Short circuit protected
Y
Performance similar to LM381
Schematic and Connection Diagrams
TL H 7845 1
Dual-In-Line Package
TL H 7845 2
Top View
Order Number LM387N or LM387AN
See NS Package Number N08E
Typical Applications
TL H 7845 3
FIGURE 1 Flat Gain Circuit (A
V
e
1000)
TL H 7845 4
FIGURE 2 NAB Tape Circuit
C1995 National Semiconductor Corporation
RRD-B30M115 Printed in U S A
Absolute Maximum Ratings
If Military Aerospace specified devices are required
please contact the National Semiconductor Sales
Office Distributors for availability and specifications
Supply Voltage
LM387
a
30V
LM387A
a
40V
Power Dissipation (Note 1)
1 5W
Operating Temperature Range
0 C to
a
70 C
Storage Temperature Range
b
65 C to
a
150 C
Lead Temperature (Soldering 10 sec )
260 C
Electrical Characteristics
T
A
e
25 C V
CC
e
14V unless otherwise stated
Parameter
Conditions
Min
Typ
Max
Units
Voltage Gain
Open Loop f
e
100 Hz
160 000
V V
Supply Current
LM387 V
CC
9V 30V R
L
e
%
10
mA
LM387A V
CC
9V 40V R
L
e
%
10
mA
Input Resistance
Positive Input
50
100
kX
Negative Input
200
kX
Input Current
0 5
3 1
m
A
Negative Input
Output Resistance
Open Loop
150
X
Output Current
Source
8
mA
Sink
2
mA
Output Voltage Swing
Peak-to-Peak
V
CC
b
2
V
Unity Gain Bandwidth
15
MHz
Large Signal Frequency
20 Vp-p (V
CC
l
24V)
75
kHz
Response
THD
s
1%
Maximum Input Voltage
Linear Operation
300
mVrms
Supply Rejection Ratio
f
e
1 kHz
110
dB
Input Referred
Channel Separation
f
e
1 kHz
40
60
dB
Total Harmonic Distortion
60 dB Gain f
e
1 kHz
0 1
0 5
%
Total Equivalent Input
10 Hz 10 000 Hz
1 0
1 2
m
Vrms
Noise (Flat Gain Cricuit)
LM387
Figure 1
Output Noise NAB Tape
Unweighted
400
700
m
Vrms
Playback Circuit Gain of 37 dB
LM387A
Figure 2
Note 1
For operation in ambient temperatures above 25 C the device must be derated based on a 150 C maximum junction temperature and a thermal resistance
of 80 C W junction to ambient
Typical Applications
(Continued)
Two-Pole Fast Turn-ON NAB Tape Preamplifier
TL H 7845 5
Frequency Response of NAB
Circuit of Figure 2
TL H 7845 6
2
Typical Performance Characteristics
V
CC
vs I
CC
Gain and Phase Response
Response
Large Signal Frequency
(Input Referred)
PSRR vs Frequency
Channel Separation
Non-Inverting Amplifier
Distortion vs Frequency
Frequency
Noise Voltage vs
Frequency
Noise Current vs
Inverting Amplifier
Distortion vs Frequency
TL H 7845 7
3
LM387LM387A
Low
Noise
Dual
Preamplifier
Typical Applications
(Continued)
Inverting Amplifier Ultra-Low Distortion
TL H 7845 8
Typical Magnetic Phono Preamplifier
TL H 7845 9
Physical Dimensions
inches (millimeters)
Molded Dual-In-Line Package (N)
Order Number LM387N or LM387AN
NS Package Number N08E
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SEMICONDUCTOR CORPORATION As used herein
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support device or system whose failure to perform can
into the body or (b) support or sustain life and whose
be reasonably expected to cause the failure of the life
failure to perform when properly used in accordance
support device or system or to affect its safety or
with instructions for use provided in the labeling can
effectiveness
be reasonably expected to result in a significant injury
to the user
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