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 outputcurrents 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 components. It is not necessary to bypass the output, although this
LM109/LM309 5-Volt Regulator
April 1998
does improve transient response somewhat. Input bypassing 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
n Specified to be compatible, worst case, with TTL and
DTL
n Output current in excess of 1A
n Internal thermal overload protection
n No external components required
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Input Voltage35V
Power DissipationInternally Limited
Operating Junction Temperature Range
LM109−55˚C to +150˚C
LM3090˚C to +125˚C
Storage Temperature Range−65˚C to +150˚C
Lead Temperature
(Soldering, 10 sec.)300˚C
Electrical Characteristics (Note 2)
ParameterConditionsLM109LM309Units
MinTypMaxMinTypMax
Output VoltageT
Line RegulationT
Load RegulationT
TO-39 Package5 mA ≤ I
TO-3 Package5 mA ≤ I
Output Voltage7.40V ≤ V
Quiescent Current7.40V ≤ VIN≤ 25V5.2105.210mA
Quiescent Current Change7.40V ≤ V
Output Noise VoltageT
Long Term Stability1020mV
Ripple RejectionT
Thermal Resistance,(Note 3)
Junction to Case
TO-39 Package1515˚C/W
TO-3 Package2.52.5˚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 ≤ T
for the TO-39 package or I
=
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.
OUT
=
=
25˚C4.75.055.34.85.055.2V
j
=
25˚C4.0504.050mV
j
7.10V ≤ V
=
j
5mA≤I
<
P
5mA≤I
A
≤ 25V
IN
25˚C
≤ 0.5A15501550mV
OUT
≤ 1.5A1510015100mV
OUT
≤ 25V,4.65.44.755.25V
IN
≤ I
OUT
P
MAX
OUT
=
25˚C4040µV
,
MAX
≤ 25V0.50.5mA
IN
≤ I
MAX
10 Hz ≤ f ≤ 100 kHz
=
25˚C5050dB
j
≤ +150˚C for the LM109 and 0˚C ≤ Tj≤ +125˚C for the LM309; V
0.5A for the TO-3 package. For the TO-39 package, I
j
MAX
0.80.8mA
=
0.2A and P
=
2.0W. For the TO-3 package, I
MAX
IN
=
10V; and I
MAX
=
1.0A and P
OUT
=
0.1A
MAX
Connection Diagrams
Metal Can Packages
DS007138-33
Order Number LM109H, LM109H/883 or LM309H
See NS Package Number H03A
www.national.com2
DS007138-34
Order Number LM109K STEEL or
LM309K STEEL
See NS Package Number K02A
Order Number LM109K/883
See NS Package Number K02C
Page 3
Application Hints
1. Bypass the input of the LM109 to ground with ≥ 0.2 µF
ceramic or solid tantalum capacitor if main filter capacitor 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 transients 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 nonexistent, 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.
Crowbar Overvoltage Protection
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 10Ω
resistor will raise +V
OUT
by ≈ 0.05V.
DS007138-7
Input Crowbar
DS007138-8
Typical Performance Characteristics
Maximum Average
Power Dissipation (LM109K)
Maximum Average
Power Dissipation (LM309K)
Output Crowbar
*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.
DS007138-9
Output Impedance
DS007138-16
DS007138-17
DS007138-18
www.national.com3
Page 4
Typical Performance Characteristics (Continued)
Maximum Average
Power Dissipation (LM109H)
DS007138-19
Current Limit
Characteristics (Note 5)
DS007138-22
Note 5: Current limiting foldback characteristics are determined by input output differential, not by output voltage.
Maximum Average
Power Dissipation (LM309H)
DS007138-20
Thermally Induced Output
Voltage Variation
DS007138-23
Ripple Rejection
DS007138-21
Ripple Rejection
DS007138-24
Input-Output Differential (V)
DS007138-25
Output Voltage (V)
www.national.com4
DS007138-26
Output Voltage (V)
DS007138-27
Page 5
Typical Performance Characteristics (Continued)
Quiescent Current
DS007138-28
Line Transient Response
DS007138-31
Typical Applications
Quiescent Current
Load Transient Response
DS007138-29
DS007138-32
Output Voltage Noise
DS007138-30
Fixed 5V Regulator
*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.
DS007138-2
Adjustable Output Regulator
DS007138-4
www.national.com5
Page 6
Typical Applications (Continued)
High Stability Regulator
*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
*
DS007138-5
*Determines output current. If wirewound resistor is used, bypass with 0.1 µF.
Mil-Aero Product
Order Number LM109K/883
NS Package Number K02C
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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
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.
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
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.