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LM325
Dual Voltage Regulator
General Description
This dual polarity tracking regulator is designed to provide
balanced positive and negative output voltages at current up
to 100 mA, and is set for
±
15V outputs. Input voltages up to
±
30V can be used and there is provision for adjustable current limiting. The device is available in two package types to
accommodate various power requirements and temperature
ranges.
Features
n
±
15V tracking outputs
n Output current to 100 mA
n Output voltage balanced to within 2
%
n Line and load regulation of 0.06
%
n Internal thermal overload protection
n Standby current drain of 3 mA
n Externally adjustable current limit
n Internal current limit
Schematic and Connection Diagrams
DS007776-1
Metal Can Package
DS007776-3
Case connected to −V
IN
Top View
Order Number LM325H
See NS Package Number H10C
June 1999
LM325 Dual Voltage Regulator
© 1999 National Semiconductor Corporation DS007776 www.national.com
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Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the NationalSemiconductorSales Office/
Distributors for availability and specifications.
Input Voltage
±
30V
Forced V
O
+
(Min) (Note 2) −0.5V
Forced V
O
−
(Max) (Note 2) +0.5V
Power Dissipation (Note 3) P
MAX
Output Short-Circuit Duration (Note 4) Continuous
Operating Conditions
Operating Free Temperature Range 0˚C to +70˚C
Storage Temperature Range −65˚C to +150˚C
Lead Temperature (Soldering, 10 sec.) 300˚C
Electrical Characteristics
Parameter Conditions Min Typ Max Units
Output Voltage T
j
=
25˚C 14.5 15 15.5 V
Input-Output Differential 2.0 V
Line Regulation V
IN
=
18V to 30V, I
L
=
20 mA,
T
j
=
25˚C
2.0 10 mV
Line Regulation Over Temperature Range V
IN
=
18V to 30V, I
L
=
20 mA, 20 20 mV
Load Regulation
V
O
+
V
O
−
I
L
=
0mAto50mA,V
IN
=
±
30V,
T
=
j
25˚C 3.0
5.0
10
10
mV
mV
Load Regulation Over Temperature Range
V
O
+
V
O
−
I
L
=
0mAto50mA,V
IN
=
±
30V
4.0
7.0
20
20
mV
mV
Output Voltage Balance T
j
=
25˚C
±
300 mV
Output Voltage Over Temperature Range P ≤ P
MAX
,0≤IO≤50 mA,
18V ≤ |V
IN
| ≤ 30
14.27 15.73 V
Temperature Stability of V
O
±
0.3
%
Short Circuit Current Limit T
j
=
25˚C 260 mA
Output Noise Voltage T
j
=
25˚C, BW=100 − 10 kHz 150 µVrms
Positive Standby Current T
j
=
25˚C 1.75 3.0 mA
Negative Standby Current T
j
=
25˚C 3.1 5.0 mA
Long Term Stability 0.2
%
/kHr
Thermal Resistance Junction to
Case (Note 5)
LM325H
Junction to Ambient
Junction to Ambient
(Still Air)
(400 Lf/min Air Flow)
20
215
82
˚C/W
˚C/W
˚C/W
Junction to Ambient
LM325N
(Still Air)
90 ˚C/W
Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits.
Note 2: That voltage to which the output may be forced without damage to the device.
Note 3: Unless otherwise specified these specifications apply for T
j
=
0˚C to +125˚C on LM325, V
IN
=
±
20V,I
L
=
0 mA, I
MAX
=
100 mA, P
MAX
=
2.0W for the H10
Package.
Note 4: If the junction temperature exceeds 150˚C, the output short circuit duration is 60 seconds.
Note 5: Without a heat sink, the thermal resistance junction to ambient of the H10 Package is about 155˚C/W. With a heat sink, the effective thermal resistance can
only approach the junction to case values specified, depending on the efficiency of the sink.
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Typical Performance Characteristics
Load Regulation
DS007776-11
Standby Current Drain
DS007776-12
Regulator Dropout Voltage
for Positive Regulator
DS007776-13
Regulator
Dropout Voltage for
Negative Regulator
DS007776-14
Peak Output
Current vs
Junction Temperature
DS007776-15
LM325 Maximum Average
Power Dissipation vs
Ambient Temperature
DS007776-17
Load Transient Response
for Positive Regulator
DS007776-20
Load Transient Response
for Negative Regulator
DS007776-21
Line Transient Response
for Positive Regulator
DS007776-22
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Typical Performance Characteristics (Continued)
Typical Applications
Line Transient Response
for Negative Regulator
DS007776-23
Ripple Rejection
DS007776-24
Output Impedance
vs Frequency
DS007776-25
Basic Regulator
†††
DS007776-6
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Typical Applications (Continued)
2.0 Amp Boosted Regulator with Current Limit
DS007776-7
Note: Metal can (H) packages shown.
†
Solid tantalum
††
Short pins 6 and 7 on dip
†††
RCLcan be added to the basic regulator between pins 6 and 5, 1 and 2 to reduce current limit.
*Required if regulator is located an appreciable distance from power supply filter.
*
*
Although no capacitor is needed for stability, it does help transient response. (If needed use 1 µF electrolytic.)
***
Although no capacitor is needed for stability, it does help transient response. (If needed use 10 µF electrolytic.)
Positive Current Dependent Simultaneous Current Limiting
DS007776-8
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Typical Applications (Continued)
Boosted Regulator With Foldback Current Limit
DS007776-9
Positive Reg.
I
MAX
=
2.0A
I
SC
+
=
750 mA
@
T
A
=
25˚C
+V
IN
=
+25V
Negative Reg.
I
MAX
=
2.0A
I
SC
=
750 mA
@
T
A
=
25˚C
−V
IN
=
−25V
Resistor Values
125 126
R1 18 20
R2 310 180
R3 2.4k 1.35k
R6 300 290
R
CL
0.7 0.9
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Typical Applications (Continued)
Electric Shutdown
DS007776-10
†
Solid tantalum
††
Short pins 6 and 7 on dip
*Required if regulator is located an appreciable distance from power supply filter.
**
Although no capacitor is needed for stability, it does help transient response. (If needed use 1 µF electrolytic.)
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Physical Dimensions inches (millimeters) unless otherwise noted
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DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
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www.national.com
Metal Can Package (H)
Order Number LM325H
NS Package Number H10C
LM325 Dual Voltage Regulator
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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