LM150QML
3-Amp Adjustable Regulators
General Description
The LM150 adjustable 3-terminal positive voltage regulator
is capable of supplying in excess of 3A over a 1.2V to 33V
output range. It is exceptionally easy to use and requires
only 2 external resistors to set the output voltage. Further,
both line and load regulation are comparable to discrete
designs. Also, the LM150 is packaged in standard transistor
package which is easily mounted and handled.
In addition to higher performance than fixed regulators, the
LM150 offers full overload protection available only in IC’s.
Included on the chip are current limit, thermal overload pro-
tection and safe area protection. All overload protection cir-
cuitry remains fully functional even if the adjustment terminal
is accidentally disconnected.
Normally, no capacitors are needed unless the device is
situated more than 6 inches from the input filter capacitors in
which case an input bypass is needed. An output capacitor
can be added to improve transient response, while bypass-
ing the adjustment pin will increase the regulator’s ripple
rejection.
Besides replacing fixed regulators or discrete designs, the
LM150 is useful in a wide variety of other applications. Since
the regulator is “floating” and sees only the input-to-output
differential voltage, supplies of several hundred volts can be
regulated as long as the maximum input to output differential
is not exceeded, i.e., avoid short-circuiting the output.
By connecting a fixed resistor between the adjustment pin
and output, the LM150 can be used as a precision current
regulator. Supplies with electronic shutdown can be
achieved by clamping the adjustment terminal to ground
which programs the output to 1.2V where most loads draw
little current.
Features
nAdjustable output down to 1.2V
nGuaranteed 3A output current
nGuaranteed thermal regulation
nOutput is short circuit protected
nCurrent limit constant with temperature
n86 dB ripple rejection
Applications
nAdjustable power supplies
nConstant current regulators
nBattery chargers
Ordering Information
NS Part Number JAN Part Number NS Package Number Package Description
LM150K/883 5962–8767501XA K02C 2LD T0–3 Metal Can
March 2006
LM150QML 3-Amp Adjustable Regulators
© 2006 National Semiconductor Corporation DS201557 www.national.com
Connection Diagram
(TO-3 STEEL)
Metal Can Package
20155704
Bottom View
See NS Package Number K02C
Schematic Diagram
20155710
LM150QML
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Absolute Maximum Ratings (Note 1)
Power Dissipation (Note 2) Internally Limited
Input-Output Voltage Differential +35V
Storage Temperature −65˚C ≤T
A
≤+150˚C
Lead Temperature (Soldering, 10 sec.) 300˚C
ESD Tolerance TBD
Operating Temperature Range −55˚C ≤T
A
≤+125˚C
Quality Conformance Inspection
Mil-Std-883, Method 5005 - Group A
Subgroup Description Temp ˚C
1 Static tests at 25
2 Static tests at 125
3 Static tests at -55
4 Dynamic tests at 25
5 Dynamic tests at 125
6 Dynamic tests at -55
7 Functional tests at 25
8A Functional tests at 125
8B Functional tests at -55
9 Switching tests at 25
10 Switching tests at 125
11 Switching tests at -55
12 Settling time at 25
13 Settling time at 125
14 Settling time at -55
LM150 Electrical Characteristics
DC Parameters
The following conditions apply, unless otherwise specified.
DC: V
Diff
= 5V, V
O
=V
Ref,I
O
= 1.5A.
Symbol Parameter Conditions Notes Min Max Unit Sub-
groups
V
Ref
Reference Voltage 1.2 1.3 V 1, 2, 3
V
Diff
= 3.0V, I
L
= 10mA 1.2 1.3 V 1, 2, 3
V
Diff
= 3.0V, I
L
= 3.0A 1.2 1.3 V 1, 2, 3
V
Diff
= 35V, I
L
= 10mA 1.2 1.3 V 1, 2, 3
V
Diff
= 10V, I
L
= 3.0A (Note 9) 1.2 1.3 V 1, 2, 3
V
Diff
= 30V, I
L
= 300mA 1.2 1.3 V 1, 2, 3
V
Line
Line Regulation 3V ≤V
Diff
≤35V, I
Load
= 10mA (Note 6),
(Note 3)
-3.8 3.8 mV 1
(Note 6),
(Note 3)
-19.0 19.0 mV 2, 3
LM150QML
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LM150 Electrical Characteristics (Continued)
DC Parameters (Continued)
The following conditions apply, unless otherwise specified.
DC: V
Diff
= 5V, V
O
=V
Ref,I
O
= 1.5A.
Symbol Parameter Conditions Notes Min Max Unit Sub-
groups
V
Load
Load Regulation 10mA ≤I
L
≤3A, V
O
=V
Ref
(Note 5),
(Note 10),
(Note 3)
-3.6 3.6 mV 1
(Note 5),
(Note 10),
(Note 3)
-12.0 12.0 mV 2, 3
V
Diff
= 30V, 10mA ≤I
L
≤300mA (Note 3) -2.0 2.0 mV 1
(Note 3) -5.0 5.0 mV 2, 3
10mA ≤I
L
≤3A, V
O
= 5.0V (Note 5),
(Note 7),
(Note 3)
-15.0 15.0 mV 1
(Note 5),
(Note 7),
(Note 3)
-50.0 50.0 mV 2, 3
T
Reg
Thermal Regulation t = 20mS (Note 8) -9.75 9.75 mV 1
I
Adj
Adjust Pin Current 100 µA 1, 2, 3
V
Diff
= 35V, I
O
= 10mA 100 µA 1, 2, 3
I
Q
Quiescent Current 5.0 mA 1, 2, 3
V
Diff
= 35V 5.0 mA 1, 2, 3
∆I
Adj
Delta Adjustment Current 3V ≤V
Diff
≤35V I
O
= 10mA -5.0 5.0 µA 1, 2, 3
10mA ≤I
L
≤3A -5.0 5.0 µA 1, 2, 3
V
Diff
= 30V, 10mA ≤I
L
≤300mA -5.0 5.0 µA 1, 2, 3
Current Limit V
Diff
= 10V 3.0 A 1, 2, 3
V
Diff
= 30V 0.3 A 1, 2, 3
∆V
O
/∆t Long Term Stability T
A
= +125˚C, t = 1000 Hrs,
V
Diff
= 3.0V, I
L
= 10mA
(Note 4) 1.0 %/V
O
2
V
Drop
Voltage Dropout V
Diff
= 2.9V, I
L
= 3A -100 100 mV 1, 2, 3
AC Parameters
Symbol Parameter Conditions Notes Min Max Unit Sub-
groups
RR Ripple Rejection ƒ = 120 Hz, e
I
=1V
RMS
,
C
Adj
= 10µF, V
O
= 10V
66 dB 4, 5, 6
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. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.
Note 2: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJmax (maximum junction temperature), θJA (package junction
to ambient thermal resistance), and TA(ambient temperature). The maximum allowable power dissipation at any temperature is PDmax =(T
Jmax -T
A)/θJA or the
number given in the Absolute Maximum Ratings, whichever is lower.
Note 3: Regulation is measured at a constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are
covered under the specifications for thermal regulation.
Note 4: Periodic Group C testing.
Note 5: These VOconditions are worst case
Note 6: Limits = 0.01% of VO@25˚C, 0.05% @−55˚C, +125˚C per volt of VDiff change at VO=V
Ref.
Note 7: Limits = 0.3% of VO@25˚C, 1.0% @−55˚C, +125˚C @VO= 5.0V.
Note 8: Limits = 0.01% of VO@25˚C per Watt of power dissipation at PD= 7.5W.
Note 9: Represents worst case power dissipation of 30W.
Note 10: Limits are equivalent to 15mV @25˚C and 50mV @−55˚C, +125˚C @VO= 5.0V.
LM150QML
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Typical Performance Characteristics
Load Regulation Current Limit
20155733 20155734
Adjustment Current Dropout Voltage
20155735 20155736
Temperature Stability Minimum Operating Current
20155737 20155738
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Typical Performance Characteristics (Continued)
Ripple Rejection Ripple Rejection
20155739 20155740
Ripple Rejection Output Impedance
20155741 20155742
Line Transient Response Load Transient Response
20155743 20155744
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Application Hints
In operation, the LM150 develops a nominal 1.25V reference
voltage, V
Ref
, between the output and adjustment terminal.
The reference voltage is impressed across program resistor
R1 and, since the voltage is constant, a constant current I
1
then flows through the output set resistor R2, giving an
output voltage of
Since the 50 µA current from the adjustment terminal repre-
sents an error term, the LM150 was designed to minimize
I
Adj
and make it very constant with line and load changes. To
do this, all quiescent operating current is returned to the
output establishing a minimum load current requirement. If
there is insufficient load on the output, the output will rise.
EXTERNAL CAPACITORS
An input bypass capacitor is recommended. A 0.1 µF disc or
1 µF solid tantalum on the input is suitable input bypassing
for almost all applications. The device is more sensitive to
the absence of input bypassing when adjustment or output
capacitors are used but the above values will eliminate the
possibility of problems.
The adjustment terminal can be bypassed to ground on the
LM150 to improve ripple rejection. This bypass capacitor
prevents ripple from being amplified as the output voltage is
increased. With a 10 µF bypass capacitor 86 dB ripple
rejection is obtainable at any output level. Increases over
10 µF do not appreciably improve the ripple rejection at
frequencies above 120 Hz. If the bypass capacitor is used, it
is sometimes necessary to include protection diodes to pre-
vent the capacitor from discharging through internal low
current paths and damaging the device.
In general, the best type of capacitors to use is solid tanta-
lum. Solid tantalum capacitors have low impedance even at
high frequencies. Depending upon capacitor construction, it
takes about 25 µF in aluminum electrolytic to equal 1 µF
solid tantalum at high frequencies. Ceramic capacitors are
also good at high frequencies, but some types have a large
decrease in capacitance at frequencies around 0.5 MHz. For
this reason, 0.01 µF disc may seem to work better than a 0.1
µF disc as a bypass.
Although the LM150 is stable with no output capacitors, like
any feedback circuit, certain values of external capacitance
can cause excessive ringing. This occurs with values be-
tween 500 pF and 5000 pF. A 1 µF solid tantalum (or 25 µF
aluminum electrolytic) on the output swamps this effect and
insures stability.
LOAD REGULATION
The LM150 is capable of providing extremely good load
regulation but a few precautions are needed to obtain maxi-
mum performance. The current set resistor connected be-
tween the adjustment terminal and the output terminal (usu-
ally 240Ω) should be tied directly to the output (case) of the
regulator rather than near the load. This eliminates line
drops from appearing effectively in series with the reference
and degrading regulation. For example, a 15V regulator with
0.05Ωresistance between the regulator and load will have a
load regulation due to line resistance of 0.05ΩxI
OUT
.Ifthe
set resistor is connected near the load the effective line
resistance will be 0.05Ω(1 + R2/R1) or in this case, 11.5
times worse.
Figure 2 shows the effect of resistance between the regula-
tor and 240Ωset resistor.
With the TO-3 package, it is easy to minimize the resistance
from the case to the set resistor, by using two separate leads
to the case. The ground of R2 can be returned near the
ground of the load to provide remote ground sensing and
improve load regulation.
PROTECTION DIODES
When external capacitors are used with any IC regulator it is
sometimes necessary to add protection diodes to prevent
the capacitors from discharging through low current points
into the regulator. Most 10 µF capacitors have low enough
internal series resistance to deliver 20A spikes when
shorted. Although the surge is short, there is enough energy
to damage parts of the IC.
When an output capacitor is connected to a regulator and
the input is shorted, the output capacitor will discharge into
the output of the regulator. The discharge current depends
on the value of the capacitor, the output voltage of the
regulator, and the rate of decrease of V
IN
. In the LM150, this
discharge path is through a large junction that is able to
sustain 25A surge with no problem. This is not true of other
types of positive regulators. For output capacitors of 25 µF or
less, there is no need to use diodes.
The bypass capacitor on the adjustment terminal can dis-
charge through a low current junction. Discharge occurs
when either the input or output is shorted. Internal to the
LM150 is a 50Ωresistor which limits the peak discharge
current. No protection is needed for output voltages of 25V
20155707
FIGURE 1.
20155708
FIGURE 2. Regulator with Line Resistance
in Output Lead
LM150QML
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Application Hints (Continued)
or less and 10 µF capacitance. Figure 3 shows an LM150
with protection diodes included for use with outputs greater
than 25V and high values of output capacitance.
Typical Applications
1.2V–25V Adjustable Regulator
20155701
Full output current not available
at high input-output voltages.
†Optional — improves transient response. Output capacitors in the range of
1 µF to 1000 µF of aluminum or tantalum electrolytic are commonly used
to provide improved output impedance and rejection of transients.
*Needed if device is more than 6 inches from filter capacitors.
Note: Usually R1 = 240Ωfor LM150 and R1 = 120Ω.
Precision Power Regulator with Low Temperature
Coefficient
20155713
*Adjust for 3.75V across R1
Slow Turn-ON 15V Regulator
20155714
20155709
D1 protects against C1
D2 protects against C2
FIGURE 3. Regulator with Protection Diodes
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Typical Applications (Continued)
Adjustable Regulator with Improved
Ripple Rejection
20155715
†Solid tantalum
*Discharges C1 if output is shorted to ground
High Stability 10V Regulator
20155716
Digitally Selected Outputs
20155717
*Sets maximum VO
Regulator and Voltage Reference
20155703
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Typical Applications (Continued)
10A Regulator
20155718
*Minimum load current 50 mA
5V Logic Regulator with
Electronic Shutdown*
20155719
*Minimum output ≈1.2V
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Typical Applications (Continued)
0 to 30V Regulator
20155720
Full output current not available at high input-output voltages
5A Constant Voltage/Constant Current Regulator
20155721
†Solid tantalum
*Lights in constant current mode
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Typical Applications (Continued)
12V Battery Charger
20155722
Adjustable Current Regulator
20155723
Precision Current Limiter
20155724
*0.4 ≤R1≤120Ω
1.2V–20V Regulator with
Minimum Program Current
20155725
*Minimum output current ≈4mA
3A Current Regulator
20155726
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Typical Applications (Continued)
Tracking Preregulator
20155727
Adjusting Multiple On-Card Regulators
with Single Control*
20155728
†Minimum load — 10 mA
*All outputs within ±100 mV
AC Voltage Regulator
20155729
Simple 12V Battery Charger
20155730
20155748
Use of RSallows low charging rates with fully charged battery.
**1000 µF is recommended to filter out any input transients
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Typical Applications (Continued)
Temperature Controller
20155711
Light Controller
20155712
Adjustable 10A Regulator
20155731
Current Limited 6V Charger
20155732
*Sets peak current (2A for 0.3Ω)
**1000 µF is recommended to filter out any input transients.
6A Regulator
20155702
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Revision History
Released Revision Section Originator Changes
03/10/06 A New Release, Corporate format L. Lytle 1 MDS data sheet converted into one Corp.
data sheet format. MNLM150-X Rev. 0BL
will be archived.
LM150QML
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Physical Dimensions inches (millimeters) unless otherwise noted
2 Lead TO-3 Metal Can Package (K)
NS Package Number K02C
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.
For the most current product information visit us at www.national.com.
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LM150QML 3-Amp Adjustable Regulators
