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LP2950/2951
Micrel
LP2950/2951
100mA Low-Dropout Voltage Regulator
General Description
Features
The LP2950 and LP2951 are micropower voltage regulators
with very low dropout voltage (typically 40mV at light loads
and 380mV at 100mA), and very low quiescent current (75µA
typical). The quiescent current of the LP2950/LP2951
increases only slightly in dropout, thus prolonging battery life.
This feature, among others, makes the LP2950 and LP2951
ideally suited for use in battery-powered systems.
Available in a 3-Pin TO-92 package, the LP2950 is pin-
compatible with the older 5V regulators. Additional system
functions, such as programmable output voltage and logic-
controlled shutdown, are available in the 8-pin DIP and 8-pin
SOIC versions of the LP2951.
Applications
• Automotive Electronics
• Voltage Reference
• Avionics
• High accuracy 5V, guaranteed 100 mA output
• Extremely low quiescent current
• Low-dropout voltage
• Extremely tight load and line regulation
• Very low temperature coefficient
• Use as regulator or reference
• Needs only 1µF for stability
• Current and thermal limiting
LP2951 Versions Only
• Error flag warns of output dropout
• Logic-controlled electronic shutdown
• Output programmable from 1.24 to 29V
Block Diagram and Pin Configurations
UNREGULATED DC
+ 78
FEEDBACK
INPUT
1
OUTPUT
FROM
CMOS
OR TTL
3
SHUT-
DOWN
60 mV
+
1.23 V +
REF.
+
ERROR
AMPLIFIER
+
182
k
60
k
ERROR
DETECTION
COMPARATOR
5V
150 mA
MAX.
2
SENSE
6
5V TAP
5
ERROR
4
GROUND
+
1.5 µF
330
k
TO CMOS
OR TTL
LP2950 and LP2951 Block Diagram
(Pin Numbers Refer to LP2951)
32 1
OUTPUT
INPUT
GROUND
OUTPUT
SENSE
SHUTDOWN
GROUND
1
2
3
4
8
INPUT
7
FEEDBACK
6
5V TAP
5
ERROR
TO-92 Plastic Package Bottom View
(BZ)
DIP and SO Packages
(BN and BM)
See MIC2950 for a part with 1) higher output (150 mA), 2) transient protection (60V), and 3) reverse input protection to –20V)
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LP2950/2951
Additional features available with the LP2951 also include an
error flag output that warns of a low output voltage, which is
often due to failing batteries on the input. This may also be
used as a power-on reset. A logic-compatible shutdown input
is also available which enables the regulator to be switched on
and off. This part may also be pin-strapped for a 5V output,
or programmed from 1.24V to 29V with the use of two external
resistors.
The LP2950 is available as either an -02 or -03 version. The
-02 and -03 versions are guaranteed for junction temperatures
Micrel
from –40°C to +125°C; the -02 version has a tighter output and
reference voltage specification range over temperature. The
LP2951 is available as an -02 or -03 version.
The LP2950 and LP2951 have a tight initial tolerance (0.5%
typical), a very low output voltage temperature coefficient
which allows use as a low-power voltage reference, and
extremely good load and line regulation (0.05% typical). This
greatly reduces the error in the overall circuit, and is the result
of careful design techniques and process control.
Ordering Information
Part Number
Voltage
LP2950-02BZ
5.0V
LP2950-03BZ
5.0V
LP2951-02BM
5.0V
LP2951-03BM
5.0V
LP2951-02BN
5.0V
LP2951-03BN
5.0V
LP2951-4.8BM
4.85V
* Junction temperatures
Temperature Range*
Package
Accuracy
–40°C to +125°C 3-Pin TO-92 plastic 0.5%
–40°C to +125°C 3-Pin TO-92 plastic 1.0%
–40°C to +125°C
8-Pin SOIC
0.5%
–40°C to +125°C
8-Pin SOIC
1.0%
–40°C to +125°C
8-Pin Plastic DIP
0.5%
–40°C to +125°C
8-Pin Plastic DIP
1.0%
–40°C to +125°C
8-Pin SOIC
1.0%
Absolute Maximum Ratings
If Military/Aerospace specified devices are required, contact your local
Micrel representative/distributor for availability and specifications.
Power dissipation
Internally Limited
Lead Temperature (Soldering, 5 seconds)
260°C
Storage Temperature Range
–65°C to +150°C
Operating Junction Temperature Range (Note 8)
LP2950, LP2951
Input Supply Voltage
–40°C to +125°C
–0.3V to +30V
Feedback Input Voltage (Notes 9 and 10)
–1.5V to +30V
Shutdown Input Voltage (Note 9)
–0.3V to +30V
Error Comparator Output Voltage (Note 9)
–0.3V to +30V
ESD Rating is to be determined.
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LP2950/2951
Electrical Characteristics Note 1 TA = 25°C except as noted.
Parameter
Condition
Output Voltage
TJ = 25°C
LP295x-02 (±0.5%)
LP295x-03 (±1%)
LP2951-4.8 (±1%)
Output Voltage
–25°C TJ +85°C
LP295x-02 (±0.5%)
LP295x-03 (±1%)
LP2951-4.8 (±1%)
Output Voltage
Over Full Temperature Range
LP295x-02 (±0.5%), –40°C to +125°C
LP295x-03 (±1%), –40°C to +125°C
LP2951-4.8 (±1%), –40°C to +125°C
Output Voltage
Over Load Variation
Output Voltage
Temperature Coefficient
LP295x-02 (±0.5%), 100µA IL 100mA, TJ TJ(max)
LP295x-03 (±1%), 100µA IL 100mA, TJ TJ(max)
LP2951-4.8 (±1%), 100µA IL 100mA, TJ TJ(max)
LP295x-02 (±0.5%), Note 12
LP295x-03 (±1%), Note 12
LP2951-4.8 (±1%), Note 12
Line Regulation
LP295x-02 (±0.5%), Notes 14, 15
LP295x-03 (±1%), Notes 14, 15
LP2951-4.8 (±1%), Notes 14, 15
Load Regulation
Dropout Voltage
Ground Current
Dropout Current
LP295x-02 (±0.5%), Note 14, 100µA IL 100mA
LP295x-03 (±1%), Note 14, 100µA IL 100mA
LP2951-4.8 (±1%), Note 14, 100µA IL 100mA
Note 5, IL = 100µA
Note 5, IL = 100mA
IL = 100µA
IL = 100mA
VIN = 4.5V, IL = 100µA
Micrel
Min
4.975
4.950
4.802
4.950
4.925
4.777
4.940
4.900
4.753
4.930
4.880
4.733
Typ
5.000
5.000
4.850
20
50
50
0.03
0.04
0.04
0.04
0.10
0.10
50
380
100
8
180
Max Units
5.025 V
5.050 V
4.899 V
5.050 V
5.075 V
4.872 V
5.060 V
5.100 V
4.947 V
5.070 V
5.120 V
4.967 V
100 ppm/°C
150 ppm/°C
150 ppm/°C
0.10 %
0.20 %
0.20 %
0.40 %
0.20 %
0.40 %
0.10 %
0.20 %
0.20 %
0.30 %
0.20 %
0.30 %
80 mV
150 mV
450 mV
600 mV
150 µA
200 µA
12 mA
14 mA
250 µA
310 µA
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LP2950/2951
Parameter
Current Limit
Thermal Regulation
Output Noise
Reference Voltage
Reference Voltage
Feedback Bias Current
Reference Voltage
Feedback Bias Current
Temperature Coefficient
Output Leakage Current
Output Low Voltage (Flag)
Upper Threshold Voltage
Lower Threshold Voltage
Hysteresis
Input Logic Voltage
Condition
VOUT = 0V
Note 13
10Hz to 100kHz, CL = 1µF
10Hz to 100kHz, CL = 200µF
10Hz to 100kHz, CL = 3.3µF,
0.01µF bypass Feedback to Output
LP295x-02 (±0.5%)
LP295x-03 (±1%)
LP2951-4.8 (±1%)
LP295x-02 (±0.5%), Note 7
LP295x-03 (±1%), Note 7
LP2951-4.8 (±1%), Note 7
LP295x-02 (±0.5%), Note 12
LP295x-03 (±1%), Note 12
LP2951-4.8 (±1%), Note 12
VOH = 30V
VIN = 4.5V, IOL = 200µA
Note 6
Note 6
Note 6
LP295x-02 (±0.5%)
Low
High
LP295x-03 (±1%)
Low
High
LP2951-4.8 (±1%)
Low
High
Micrel
Min Typ Max Units
160 200 mA
220 mA
0.05 0.20 %/W
430 µVRMS
160 µVRMS
100 µVRMS
1.220
1.200
1.210
1.200
1.210
1.200
1.190
1.185
1.185
1.235
1.235
1.235
20
20
50
50
0.1
1.250
1.260
V
V
1.260
1.270
V
V
1.260
1.270
V
V
1.270 V
1.285 V
1.285 V
40 nA
60 nA
ppm/°C
ppm/°C
ppm/°C
nA/°C
0.01 1.00
2.00
µA
µA
150 250 mV
400 mV
40 60
25
mV
mV
75 95 mV
140 mV
15 mV
1.3
0.7
2.0
V
V
V
1.3
0.7
2.0
V
V
V
1.3
0.7
2.0
V
V
V
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LP2950/2951
Micrel
Parameter
Shutdown Input Current
Regulator Output Current
in Shutdown
Condition
VSHUTDOWN = 2.4V
VSHUTDOWN = 30V
Note 11
Min Typ Max Units
30 50 µA
100 µA
450 600
750
µA
µA
3 10 µA
20 µA
Note 1: Boldface limits apply at temperature extremes.
Note 2: Unless otherwise specified all limits guaranteed for TJ = 25°C, VIN = 6V, IL = 100µA and CL = 1µF. Additional conditions for the 8-pin versions
are Feedback tied to 5V Tap and Output tied to Output Sense (VOUT = 5V) and VSHUTDOWN 0.8V.
Note 3: Guaranteed and 100% production tested.
Note 4: Guaranteed but not 100% production tested. These limits are not used to calculate outgoing AQL levels.
Note 5: Dropout voltage is defined as the input to output differential at which the output voltage drops 100mV below its nominal value measured at 1V
differential. At very low values of programmed output voltage, the minimum input supply voltage of 2V (2.3V over temperature) must be taken
into account.
Note 6:
Comparator thresholds are expressed in terms of a voltage differential at the Feedback terminal below the nominal reference voltage
measured at 6V input. To express these thresholds in terms of output voltage change, multiply by the error amplifier gain = VOUT /VREF =
(R1 + R2)/R2. For example, at a programmed output voltage of 5V, the Error output is guaranteed to go low when the output drops by
95mV x 5V/1.235V = 384mV. Thresholds remain constant as a percent of VOUT as VOUT is varied, with the dropout warning occurring at
typically 5% below nominal, 7.5% guaranteed.
Note 7:
Note 8:
VREF VOUT (VIN – 1 V), 2.3V VIN 30V, 100µA < IL 100mA, TJ TJMAX.
The junction-to-ambient thermal resistance of the TO-92 package is 180°C/W with 0.4” leads and 160°C/W with 0.25” leads to a PC board.
The thermal resistance of the 8-pin DIP package is 105°C/W junction-to-ambient when soldered directly to a PC board. Junction-to-ambient
thermal resistance for the SOIC (M) package is 160°C/W.
Note 9: May exceed input supply voltage.
Note 10: When used in dual-supply systems where the output terminal sees loads returned to a negative supply, the output voltage should be diode-
clamped to ground.
Note 11: VSHUTDOWN 2V, VIN 30 V, VOUT = 0, with Feedback pin tied to 5V Tap.
Note 12: Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
Note 13: Thermal regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or line
regulation effects. Specifications are for a 50mA load pulse at VIN = 30V (1.25W pulse) for t = 10ms.
Note 14: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating
effects are covered in the specification for thermal regulation.
Note 15: Line regulation for the LP2951 is tested at 150°C for IL = 1mA. For IL = 100µA and TJ = 125°C, line regulation is guaranteed by design to
0.2%. See Typical Performance Characteristics for line regulation versus temperature and load current.
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