LM109,LM309
LM109/LM309 5-Volt Regulator
Literature Number: SNVS752A
LM109/LM309
5-Volt Regulator
General Description
The LM109 series are complete 5V regulators fabricated on
a single silicon chip. They are designed for local regulation
on digital logic cards, eliminating the distribution problems
association with single-point regulation. The devices are
available in two standard transistor packages. In the
solid-kovar TO-5 header, it can deliver output currents in
excess of 200 mA, if adequate heat sinking is provided. With
the TO-3 power package, the available output current is
greater than 1A.
The regulators are essentially blowout proof. Current limiting
is included to limit the peak output current to a safe value. In
addition, thermal shutdown is provided to keep the IC from
overheating. If internal dissipation becomes too great, the
regulator will shut down to prevent excessive heating.
Considerable effort was expended to make these devices
easy to use and to minimize the number of external compo-
nents. It is not necessary to bypass the output, although this
does improve transient response somewhat. Input bypass-
ing is needed, however, if the regulator is located very far
from the filter capacitor of the power supply. Stability is also
achieved by methods that provide very good rejection of load
or line transients as are usually seen with TTL logic.
Although designed primarily as a fixed-voltage regulator, the
output of the LM109 series can be set to voltages above 5V,
as shown. It is also possible to use the circuits as the control
element in precision regulators, taking advantage of the
good current-handling capability and the thermal overload
protection.
Features
nSpecified to be compatible, worst case, with TTL and
DTL
nOutput current in excess of 1A
nInternal thermal overload protection
nNo external components required
Schematic Diagram
DS007138-1
April 1998
LM109/LM309 5-Volt Regulator
© 2001 National Semiconductor Corporation DS007138 www.national.com
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Input Voltage 35V
Power Dissipation Internally Limited
Operating Junction Temperature Range
LM109 −55˚C to +150˚C
LM309 0˚C to +125˚C
Storage Temperature Range −65˚C to +150˚C
Lead Temperature
(Soldering, 10 sec.) 300˚C
Electrical Characteristics (Note 2)
Parameter Conditions LM109 LM309 Units
Min Typ Max Min Typ Max
Output Voltage T
j
= 25˚C 4.7 5.05 5.3 4.8 5.05 5.2 V
Line Regulation T
j
= 25˚C 4.0 50 4.0 50 mV
7.10V ≤V
IN
≤25V
Load Regulation T
j
= 25˚C
TO-39 Package 5 mA ≤I
OUT
≤0.5A 15 50 15 50 mV
TO-3 Package 5 mA ≤I
OUT
≤1.5A 15 100 15 100 mV
Output Voltage 7.40V ≤V
IN
≤25V, 4.6 5.4 4.75 5.25 V
5mA≤I
OUT
≤I
MAX
,
P<P
MAX
Quiescent Current 7.40V ≤V
IN
≤25V 5.2 10 5.2 10 mA
Quiescent Current Change 7.40V ≤V
IN
≤25V 0.5 0.5 mA
5mA≤I
OUT
≤I
MAX
0.8 0.8 mA
Output Noise Voltage T
A
= 25˚C 40 40 µV
10 Hz ≤f≤100 kHz
Long Term Stability 10 20 mV
Ripple Rejection T
j
= 25˚C 50 50 dB
Thermal Resistance, (Note 3)
Junction to Case
TO-39 Package 15 15 ˚C/W
TO-3 Package 2.5 2.5 ˚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: Unless otherwise specified, these specifications apply −55˚C ≤Tj≤+150˚C for the LM109 and 0˚C ≤Tj≤+125˚C for the LM309; VIN = 10V; and IOUT =
0.1A for the TO-39 package or IOUT = 0.5A for the TO-3 package. For the TO-39 package, IMAX = 0.2A and PMAX = 2.0W. For the TO-3 package, IMAX = 1.0A and
PMAX = 20W.
Note 3: Without a heat sink, the thermal resistance of the TO-39 package is about 150˚C/W, while that of the TO-3 package is approximately 35˚C/W. With a heat
sink, the effective thermal resistance can only approach the values specified, depending on the efficiency of the sink.
Note 4: Refer to RETS109H drawing for LM109H or RETS109K drawing for LM109K military specifications.
Connection Diagrams
Metal Can Packages
DS007138-33
Order Number LM109H, LM109H/883 or LM309H
See NS Package Number H03A DS007138-34
Order Number LM109K STEEL or
LM309K STEEL
See NS Package Number K02A
Order Number LM109K/883
See NS Package Number K02C
LM109/LM309
www.national.com 2
Application Hints
1. Bypass the input of the LM109 to ground with ≥0.2 µF
ceramic or solid tantalum capacitor if main filter capaci-
tor is more than 4 inches away.
2. Avoid insertion of regulator into “live” socket if input
voltage is greater than 10V. The output will rise to within
2V of the unregulated input if the ground pin does not
make contact, possibly damaging the load. The LM109
may also be damaged if a large output capacitor is
charged up, then discharged through the internal clamp
zener when the ground pin makes contact.
3. The output clamp zener is designed to absorb tran-
sients only. It will not clamp the output effectively if a
failure occurs in the internal power transistor structure.
Zener dynamic impedance is ≈4Ω. Continuous RMS
current into the zener should not exceed 0.5A.
4. Paralleling of LM109s for higher output current is not
recommended. Current sharing will be almost nonexist-
ent, leading to a current limit mode operation for devices
with the highest initial output voltage. The current limit
devices may also heat up to the thermal shutdown point
(≈175˚C). Long term reliability cannot be guaranteed
under these conditions.
5. Preventing latchoff for loads connected to negative
voltage:
If the output of the LM109 is pulled negative by a high
current supply so that the output pin is more than 0.5V
negative with respect to the ground pin, the LM109 can latch
off. This can be prevented by clamping the ground pin to the
output pin with a germanium or Schottky diode as shown. A
silicon diode (1N4001) at the output is also needed to keep
the positive output from being pulled too far negative. The
10Ωresistor will raise +V
OUT
by ≈0.05V.
Crowbar Overvoltage Protection
Typical Performance Characteristics
DS007138-7
Input Crowbar
DS007138-8
Output Crowbar
DS007138-9
*Zener is internal to LM109.
**Q1 must be able to withstand 7A continuous current if fusing is not used
at regulator input. LM109 bond wires will fuse at currents above 7A.
†Q2 is selected for surge capability. Consideration must be given to filter
capacitor size, transformer impedance, and fuse blowing time.
††Trip point is ≈7.5V.
Maximum Average
Power Dissipation (LM109K)
DS007138-16
Maximum Average
Power Dissipation (LM309K)
DS007138-17
Output Impedance
DS007138-18
LM109/LM309
www.national.com3
Typical Performance Characteristics (Continued)
Maximum Average
Power Dissipation (LM109H)
DS007138-19
Maximum Average
Power Dissipation (LM309H)
DS007138-20
Ripple Rejection
DS007138-21
Current Limit
Characteristics (Note 5)
DS007138-22
Thermally Induced Output
Voltage Variation
DS007138-23
Ripple Rejection
DS007138-24
Note 5: Current limiting foldback characteristics are determined by input output differential, not by output voltage.
Input-Output Differential (V)
DS007138-25
Output Voltage (V)
DS007138-26
Output Voltage (V)
DS007138-27
LM109/LM309
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Typical Performance Characteristics (Continued)
Typical Applications
Quiescent Current
DS007138-28
Quiescent Current
DS007138-29
Output Voltage Noise
DS007138-30
Line Transient Response
DS007138-31
Load Transient Response
DS007138-32
Fixed 5V Regulator
DS007138-2
*Required if regulator is located more than 4" from power supply filter
capacitor.
†Although no output capacitor is needed for stability, it does improve
transient response.
C2 should be used whenever long wires are used to connect to the load,
or when transient response is critical.
Note: Pin 3 electrically connected to case.
Adjustable Output Regulator
DS007138-4
LM109/LM309
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Typical Applications (Continued)
High Stability Regulator*
DS007138-5
*Regulation better than 0.01%, load, line and temperature, can be obtained.
†Determines zener current. May be adjusted to minimize thermal drift.
‡Solid tantalum.
Current Regulator
DS007138-6
*Determines output current. If wirewound resistor is used, bypass with 0.1 µF.
LM109/LM309
www.national.com 6
Physical Dimensions inches (millimeters) unless otherwise noted
Metal Can Package (H)
Order Number LM109H, LM109H/883 or LM309H
NS Package Number H03A
Metal Can Package (K)
Order Number LM109K STEEL, LM309K STEEL
NS Package Number K02A
LM109/LM309
www.national.com7
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
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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:
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accordance with instructions for use provided in the
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Email: support@nsc.com
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www.national.com
Metal Can Package (K)
Mil-Aero Product
Order Number LM109K/883
NS Package Number K02C
LM109/LM309 5-Volt 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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