LP2950/LP2951
100mA Low Dropout Voltage Regulators
•
5.0V and 3.3V Versions at 100mA Output
•
Very Low Quiescent Current
•
Low Dropout Voltage: 380mV at 100mA
•
Extremely Tight Load and Line Regulation
•
Very Low Temperature Coefficient
•
Current & Thermal Limiting
•
Need Only 1
µF
for Stability
•
Offered in TO-92 (LP2950) & SOIC (LP2951)
•
Direct Replacement For LP2950/LP2951
FEATURES
•
Battery Powered Systems
•
Cordless Telephones
•
Radio Control Systems
•
Portable/Palm Top/Notebook Computers
•
Portable Consumer Equipment
•
Portable Instrumentation
•
Avionics
•
SMPS Post-Regulator
•
Voltage Reference
•
Automotive Electronics
APPLICATIONS
LP2951 versions only
•
Error Flag Warns of Output Dropout
•
Logic-Controlled Electronic Shutdown
•
Output Programmable From 1.24 to 29V
Now available in Lead Free
PRODUCT DESCRIPTION
The LP2950 and LP2951 are low power voltage regulators. These devices are an excellent choice for use in battery-powered
applications such as cordless telephones, radio control systems, and portable computers. The LP2950 and LP2951 feature low
quiescent current and low dropout voltage (typ. 50mV at light load and 380 mV at 100mA). This includes a tight initial tolerance
(0.5% typ.), extremely good load and line regulation (0.05% typ.), and very low output temperature coefficient (20 ppm/¡C typ.),
making the LP2950/LP2951 useful as a low-power voltage reference.
The error flag output feature is used as a power-on reset for warning of a low output voltage, due to a falling input voltage. The logic-
compatible shutdown feature enables the regulator to be switched ON and OFF. The LP2950 is offered in a 3-pin TO-92 package
compatible with other 5V, 3.3V regulators. The LP2951 is available in an 8-lead SOIC package.
Block diagram of LP2951
UNREGULATED DC
+
7
FEEDBACK
8
INPUT
1
OUTPUT
5V @ 100mA
MAX
2
SENSE
+
_
FROM
CMOS OR
TTL
180kΩ
6
ERROR
AMPLIFIER
5V TAP
3
SHUTDOWN
60 mV
330kΩ
+
60kΩ
+
5
______
ERROR
+
_
ERROR DETECTION
COMPARATOR
1µF
.
.
TO CMOS OR
TTL
+
1.23V
4
REFERENCE
GROUND
Rev. 8/6/01
LP2950/51 100mA Low Dropout Voltage Regulators
1
©Copyright 2001 Sipex Corporation
LP2950/51
ABSOLUTE MAXIMUM RATINGS
Power Dissipation.....................................Internally Limited
Lead Temp. (Soldering, 5 Seconds)............................260¡C
Storage Temperature Range ......................... -65¡ to +150¡C
Operating Junction Temperature Range
-40C to +125C
Input Supply Voltage..................................... -0.3V to +30V
Feedback Input Voltage................................................ -1.5V to +30V
Shutdown Input Voltage............................................... -0.3V to +30V
Error Comparator Output ............................................. -0.3V to +30V
ESD Rating .........................................................................2kV Min
ELECTRICAL CHARACTERISTICS
V
IN
=6V, I
O
=100µA, C
OUT
=1µF (Note 2) T
A
=25C,
unless otherwise noted
.
PARAMETER
3.3 V Versions
Output Voltage
CONDITIONS
LP2950AC
LP2951AC
Min.
Typ. Max.
3.284
3.267
3.260
3.254
3.3
3.3
3.3
3.3
3.317
3.333
3.340
3.346
Min.
3.267
3.251
3.234
3.221
LP2950C
LP2951C
Typ. Max.
3.3
3.3
3.3
3.3
3.333
3.350
3.366
3.379
UNITS
V
TJ = 25¡C
-25¡C
≤T
J
≤85¡C
Full Operating Temperature
100
µA ≤I
L
≤100
mA
TJ
≤T
JMAX
T
J
= 25¡C
-25¡C
≤T
J
≤85¡C
Full Operating Temperature
100
µA ≤I
L
≤100
mA
T
J
≤T
JMAX
Output Voltage
5 V Versions
Output Voltage
V
Output Voltage
All Voltage Options
Output Voltage
Temperature Coefficient
Line Regulation (Note 3)
Load Regulation (Note 3)
Dropout Voltage
(Note 5)
Ground Current
Current Limit
Thermal Regulation
Output Noise,
10Hz to 100KHz
4.975
4.950
4.940
4.925
5.0
5.0
5.0
5.0
5.025
5.050
5.060
5.075
4.950
4.925
4.900
4.880
5.0
5.0
5.0
5.0
5.050
5.075
5.100
5.120
V
V
20
(Note 1)
6V
≤V
IN
≤30V
(Note 4)
100
µA ≤I
L
≤
100 mA
I
L
= 100
µA
I
L
= 100 mA
I
L
= 100
µA
I
L
= 100 mA
V
OUT
= 0
C
L
= 1µF
C
L
= 200
µF
C
L
= 3.3
µF,
Bypass = 0.01µF
from Pin 7 to Pin 1 (LP2951)
0.03
0.04
50
380
150
8
150
0.05
430
160
100
120
0.1
0.1
80
450
170
12
200
0.2
50
0.04
0.1
50
380
150
8
150
0.05
430
160
100
150
0.2
0.2
80
450
170
12
200
0.2
ppm/¡C
%
%
mV
mV
µA
mA
mA
%/W
µV
rms
µV
rms
µV
rms
8-Pin Versions only
Reference Voltage
Reference Voltage
Over Temperature (Note 6)
LP2951AC
1.220
1.235
1.250
1.190
1.270
1.210
1.185
LP2951C
1.235
1.260
1.285
V
V
Feedback Pin Bias
Current
40
60
40
60
nA
Rev. 8/6/01
LP2950/51 100mA Low Dropout Voltage Regulators
2
©Copyright 2001 Sipex Corporation
LP2950/51
PARAMETER
8-Pin Versions only (Continued)
Reference Voltage
Temperature
Coefficient
Feedback Pin Bias
Current
Temperature Coefficient
Error Comparator
Output Leakage Current
Output Low Voltage
Upper Threshold
Voltage
Lower Threshold
Voltage
Hysteresis
Shutdown Input
Input logic Voltage
Shut down Pin Input
Current
Regulator Output
Current in Shutdown
Low (Regulator ON)
High (Regulator OFF)
V
S
= 2.4V
V
S
= 30V
(Note 8)
1.3
2.0
30
675
3
50
800
10
0.7
2.0
30
675
3
50
800
10
1.3
0.7
V
V
µA
µA
µA
V
OH
= 30V
V
IN
= 4.5V
I
OL
= 400µA
(Note 7)
(Note 7)
(Note 7)
CONDITIONS
(Note 2)
Min.
LP2951AC
Typ. Max.
20
Min.
LP2951C
Typ. Max.
50
UNITS
ppm/¡C
0.1
0.1
nA/¡C
0.01
150
40
60
75
15
1
250
40
95
0.01
150
60
75
15
1
250
µA
mV
mV
95
mV
mV
Note 1:
Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range.
Note 2:
Unless otherwise specified all limits guaranteed for T
J
= 25°C, V
IN
= 6V, I
L
= 100µA and C
L
= 1µF. Additional conditions for the 8-pin versions are feedback
tied to 5V tap and output tied to output sense (V
OUT
= 5V) and V
SHUTDOWN
≤
0.8V.
Note 3:
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 under the specification for thermal regulation.
Note 4:
Line regulation for the LP2951 is tested at I
L
= 1mA. For I
L
= 100
µA
and T
J
= 125°C, line regulation is guaranteed by design to 0.2%. See typical
performance characteristics for line regulation versus temperature and load current.
Note 5:
Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV 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:
V
REF
≤V
OUT
≤
(V
IN
- 1V), 2.3
≤V
IN
≤30V,
100µA≤I
L
≤
100mA, T
J
≤
T
JMAX
.
Note 7:
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 = V
OUT
/V
REF
= (R
1
+ R
2
)/R
2
. For example, at a programmed output
voltage of 5V, the error output is guaranteed to go low when the output drops by 95 mV x 5V/1.235 = 384 mV. Thresholds remain constant as a percent of V
OUT
as V
OUT
is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed.
Note 8:
V
SHUTDOWN
≥
2V, V
IN
≤
30V, V
OUT
=0, Feedback pin tied to 5V Tap.
Note 9:
All typical values are not guaranteed. The value could vary from lot to lot.
Rev. 8/6/01
LP2950/51 100mA Low Dropout Voltage Regulators
3
©Copyright 2001 Sipex Corporation
LP2950/ LP2951
TYPICAL PERFORMANCE CHARACTERISTIC
6
5
OUTPUT VOLTAGE (VOLTS)
INPUT CURRENT (µA)
250
225
R
L
= 50kΩ
10
4
R
L
=
175
150
125
100
75
50
25
0
GROUND PIN CURRENT (mA)
200
1
3
R
L
=50kΩ
8
2
1
0
0
1
2
3
4
5
6
INPUT VOLTAGE (VOLTS)
R
L
=
8
0.1
0
1
2
3
4
5
6
7
8
9 10
0.01
0.1
1
10
100
INPUT VOLTAGE (VOLTS)
LOAD CURRENT (mA)
Dropout Characteristics
Input Current
Quiescent Current
320
280
GROUND CURRENT (µA)
INPUT CURRENT (mA)
240
200
160
I
L
= 0
I
L
= 1mA
120
80
40
0
0
1
2
3
4
5
6
7
8
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
0
1
2
3
4
5
6
16
GROUND CURRENT (mA)
R
L
=50
Ω
V
OUT
= 5V
12
V
IN
= 6V
I
L
= 100mA
8
4
7
8
9 10
-75 -50 -25
0
25 50
75 100 125 150
TEMPERATURE (ºC)
INPUT VOLTAGE (VOLTS)
INPUT VOLTAGE (VOLTS)
Ground Current
16
14
Input Current
190
Ground Current
QUIESCENT CURRENT (µA)
GROUND CURRENT (mA)
12
I
L
=100mA
170
V
IN
=6V
I
L
=100uA
10
8
6
4
2
0
0
1
2
3
4
5
6
7
8
150
130
-75 -50 -25
0
25 50
75 100 125 150
INPUT VOLTAGE
TEMPERATURE (ºC)
Ground Current
Quiescent Current
Rev. 8/6/01
LP2950/51 100mA Low Dropout Voltage Regulators
4
©Copyright 2001 Sipex Corporation
LP2950/LP2951
TYPICAL PERFORMANCE CHARACTERISTICS
(continued)
600
I
L
= 100mA
500
170
160
SHORT CIRCUIT CURRENT (mA)
500
DROP-OUT VOLTAGE (mV)
DROP-OUT VOLTAGE (mV)
400
150
140
130
120
110
110
-75 -50 -25
400
300
~
~
300
200
T
J
= 25ºC
100
50
0
-75 -50 -25
0
25 50
75 100 125 150
I
L
= 100µA
100
0
100µA
1mA
10mA
100mA
0
25 50
75 100 125 150
TEMPERATURE (ºC)
OUTPUT CURRENT
TEMPERATURE (ºC)
Drop-Out Voltage
8
V
OUT
= 5V
Drop-Out Voltage
2.5
T
A
= 125ºC
Short Circuit Current
100
mV
50
mV
INPUT OUTPUT VOLTAGE
VOLTAGE CHANGE
6
COMPARATOR OUTPUT (V)
SINK CURRENT (mA)
2.0
4
HYSTERESIS
0
-50
mV
~
~
8V
6V
4V
0
200
400
TIME(µs)
C
L
= 1µF
I
L
= 1mA
V
OUT
= 5V
1.5
T
A
= 25ºC
2
0
-2
0
1
PULLUP RESISTOR TO
SEPARATE 5V SUPPLY
1.0
T
A
= -55ºC
0.5
0.0
2
3
4
5
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
OUTPUT LOW VOLTAGE (V)
INPUT VOLTAGE (V)
600
800
Error Comparator Output
10
I
O
= 100µA
LP2951 Comparator Sink Current
90
80
RIPPLE REJECTION (dB)
Line Transient Response
90
80
RIPPLE REJECTION (dB)
C
L
= 1µF
V
IN
= 6V
V
OUT
= 5V
OUTPUT IMPEDANCE (OHMS)
5
2
1
0.5
0.2
0.1
0.05
0.02
0.01
10
100
1K
10K
100K
1M
FREQUENCY (Hz)
V
OUT
= 5V
C
L
= 1µF
I
O
= 1mA
I
O
= 100mA
70
I
L
= 0
70
60
50
40
30
20
I
L
= 1mA
60
50
40
30
20
10
1
10
2
10
3
10
4
10
5
10
6
C
L
= 1µF
V
IN
= 6V
V
OUT
= 5V
I
L
= 100µA
I
L
= 10mA
10
1
10
2
10
3
10
4
10
5
10
6
FREQUENCY (Hz)
FREQUENCY (Hz)
Output Impedance
Ripple Rejection
Ripple Rejection
Rev. 8/6/01
LP2950/51 100mA Low Dropout Voltage Regulators
5
©Copyright 2001 Sipex Corporation
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