LP2950/LP2951 Series of Adjustable Micropower Voltage Regulators
July 2000
LP2950/LP2951
Series of Adjustable Micropower Voltage Regulators
General Description
The LP2950 and LP2951 are micropower voltage regulators
with very low quiescent current (75 µA typ.) and very low
dropout voltage (typ. 40 mV at light loads and 380 mV at
100 mA). They are ideally suited for use in battery-powered
systems. Furthermore, the quiescent current of the LP2950/
LP2951 increases only slightly in dropout, prolonging battery
life.
The LP2950-5.0 is available in the surface-mount D-Pak
package, and in the popular 3-pin TO-92 package for
pin-compatibility with older 5V regulators. The 8-lead
LP2951 is available in plastic, ceramic dual-in-line, or metal
can packages and offers additional system functions.
One such feature is an error flag output which warns of a low
output voltage, often due to falling batteries on the input. It
may be used for a power-on reset. A second feature is the
logic-compatible shutdown input which enables the regulator
to be switched on and off. Also, the part may be pin-strapped
for a 5V, 3V, or 3.3V output (depending on the version), or
programmed from 1.24V to 29V with an external pair of re-
sistors.
Careful design of the LP2950/LP2951 has minimized all con-
tributions to the error budget. This includes a tight initial tol-
erance (.5% typ.), extremely good load and line regulation
(.05% typ.) and a very low output voltage temperature coef-
ficient, making the part useful as a low-power voltage refer-
ence.
Features
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5V, 3V, and 3.3V versions available
High accuracy output voltage
Guaranteed 100 mA output current
Extremely low quiescent current
Low dropout voltage
Extremely tight load and line regulation
Very low temperature coefficient
Use as Regulator or Reference
Needs minimum capacitance for stability
Current and Thermal Limiting
Stable with low-ESR output capacitors
LP2951 versions only
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Error flag warns of output dropout
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Logic-controlled electronic shutdown
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Output programmable from 1.24 to 29V
Block Diagram and Typical Applications
LP2950
LP2951
DS008546-25
DS008546-1
© 2000 National Semiconductor Corporation
DS008546
www.national.com
LP2950/LP2951
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 Supply Voltage
SHUTDOWN Input Voltage,
Error Comparator Output
Voltage, (Note 9)
FEEDBACK Input Voltage
(Note 9) (Note 10)
Power Dissipation
Junction Temperature (T
J
)
Ambient Storage Temperature
−0.3 to +30V
Soldering Dwell Time, Temperature
Wave
Infrared
Vapor Phase
ESD
4 seconds, 260˚C
10 seconds, 240˚C
75 seconds, 219˚C
TBD
Operating Ratings
(Note 1)
Maximum Input Supply Voltage
Junction Temperature Range
(T
J
) (Note 8)
LP2951
LP2950AC-XX, LP2950C-XX,
LP2951AC-XX, LP2951C-XX
30V
−1.5 to +30V
Internally Limited
+150˚C
−65˚ to +150˚C
−55˚ to +150˚C
−40˚ to +125˚C
Electrical Characteristics
(Note 2)
LP2951
Parameter
Conditions
(Note 2)
Typ
Tested
Limit
(Notes 3, 16)
3V VERSIONS
(Note 17)
Output Voltage
T
J
= 25˚C
−25˚C
≤
T
J
≤
85˚C
Full Operating
Temperature Range
Output Voltage
3.3V VERSIONS
(Note 17)
Output Voltage
T
J
= 25˚C
−25˚C
≤
T
J
≤
85˚C
Full Operating
Temperature Range
Output Voltage
5V VERSIONS
(Note 17)
Output Voltage
T
J
= 25˚C
−25˚C
≤
T
J
≤
85˚C
Full Operating
Temperature Range
Output Voltage
ALL VOLTAGE OPTIONS
Output Voltage
Temperature Coefficient
Line Regulation
(Note 14)
Load Regulation
(Note 14)
(Note 12)
(V
O
NOM + 1)V
≤
V
in
≤
30V
(Note 15)
100 µA
≤
I
L
≤
100 mA
20
0.03
0.04
120
0.1
0.5
0.1
0.3
0.04
0.1
0.2
20
0.03
0.1
0.2
0.1
0.2
0.3
100
50
0.04
0.2
0.4
150
ppm/˚C
% max
% max
% max
% max
100 µA
≤
I
L
≤
100 mA
T
J
≤
T
JMAX
5.0
5.0
5.0
5.0
5.06
4.94
5.075
4.925
5.0
5.025
4.975
5.0
5.0
5.0
5.025
4.975
5.05
4.95
5.06
4.94
5.075
4.925
5.0
5.0
5.0
5.0
5.05
4.95
5.075
4.925
5.1
4.9
5.12
4.88
V max
V min
V max
V min
V max
V min
V max
V min
100 µA
≤
I
L
≤
100 mA
T
J
≤
T
JMAX
3.3
3.3
3.3
3.3
3.340
3.260
3.350
3.251
3.3
3.317
3.284
3.3
3.3
3.3
3.317
3.284
3.333
3.267
3.340
3.260
3.346
3.254
3.3
3.3
3.3
3.3
3.333
3.267
3.350
3.251
3.366
3.234
3.379
3.221
V max
V min
V max
V min
V max
V min
V max
V min
100 µA
≤
I
L
≤
100 mA
T
J
≤
T
JMAX
3.0
3.0
3.0
3.0
3.036
2.964
3.045
2.955
3.0
3.015
2.985
3.0
3.0
3.0
3.015
2.985
3.030
2.970
3.036
2.964
3.042
2.958
3.0
3.0
3.0
3.0
3.030
2.970
3.045
2.955
3.060
2.940
3.072
2.928
V max
V min
V max
V min
V max
V min
V max
V min
Typ
LP2950AC-XX
LP2951AC-XX
Tested
Limit
(Note 3)
Design
Limit
(Note 4)
Typ
LP2950C-XX
LP2951C-XX
Tested
Limit
(Note 3)
Design
Limit
(Note 4)
Units
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