LP2950*/2951
100mA Low-Dropout Voltage Regulator
General Description
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 (75A 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.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
•
•
•
•
•
•
High accuracy 5V, guaranteed 100mA 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
LP2951 Versions Only
•
Current and thermal limiting
•
Error flag warns of output dropout
•
Logic-controlled electronic shutdown
•
Output programmable from 1.24 to 29V
Applications
•
Automotive electronics
•
Voltage reference
•
Avionics
___________________________________________________________________________________________________________
Block Diagram
LP2590 and LP2951 Block Diagram
(Pin Numbers Refer to LP2591)
* LP2950 Discontinuance September 2007.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
September 2008
M9999-091208
Micrel, Inc.
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 a -02 or -03 version.
The -02 and -03 versions are guaranteed for junction
temperatures 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
LP2950-02BZ*
LP2950-03BZ*
LP2951-02BM
LP2951-03BM
LP2951-02BN
LP2951-03BN**
LP2951-02YM
LP2951-03YM
LP2951-02YN
Note:
* TO-92 Package discontinuance notification issued September 2007. End-of-life-buy offer thru December 31, 2007. Contact factory for
additional information.
** Contact factory for Pb-Free version.
Voltage
5.0V
5.0V
5.0V
5.0V
5.0V
5.0V
5.0V
5.0V
5.0V
Accuracy
0.5%
1.0%
0.5%
1.0%
0.5%
1.0%
0.5%
1.0%
0.5%
Junction
Temperature Range
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
Package
3-Pin TO-92 Plastic
3-Pin TO-92 Plastic
8-Pin SOIC
8-Pin SOIC
8-Pin Plastic DIP
8-Pin Plastic DIP
8-Pin SOIC
8-Pin SOIC
8-Pin Plastic DIP
Lead Finish
Standard
Standard
Standard
Standard
Standard
Standard
Pb-Free
Pb-Free
Pb-Free
Pin Configuration
TO-92 (Z)
(Bottom View)
DIP (N) and SOIC (M)
See MIC2950 for a part with: 1) higher output (150mA), 2) transient protection (60V), and 3) reverse input protection to –20V.
September 2008
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M9999-091208
Micrel, Inc.
LP2950/2951
Absolute Maximum Ratings
(1)
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 sec.)........................ 260°C
Storage Temperature ................................–65°C to +150°C
Operating Junction Temperature Range
(8)
LP2950, LP2951 .................................–40°C to +125°C
Input Supply Voltage ........................................–0.3 to +30V
Feedback Input Voltage
(9, 10)
............................–1.5 to +30V
Shutdown Input Voltage
(9)
................................–0.3 to +30V
Error Comparator Output Voltage
(9)
.................–0.3 to +30V
ESD Rating is to be determined
Electrical Characteristics
(1)
T
A
= 25°C except as noted.
Parameter
Output Voltage
T
J
= 25°C
Condition
LP295x-02 (±0.5%)
LP295x-03 (±1%)
LP2951-4.8 (±1%)
Output Voltage
–25°C
≤
T
J
≤
+85°C
LP295x-02 (±0.5%)
LP295x-03 (±1%)
LP2951-4.8 (±1%)
Output Voltage
Over Full Temperature Range
–40°C to +125°C
Output Voltage
Over Load Variation
LP295x-02 (±0.5%)
LP295x-03 (±1%)
LP2951-4.8 (±1%)
LP295x-02 (±0.5%), 100µA
≤
I
L
≤
100mA, T
J
≤
T
J(max)
LP295x-03 (±1%), 100µA
≤
I
L
≤
100mA, T
J
≤
T
J(max)
LP2951-4.8 (±1%), 100µA
≤
I
L
≤
100mA, T
J
≤
T
J(max)
Output Voltage
Temperature Coefficient
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
LP295x-02 (±0.5%),
Note 14,
100µA
≤
I
L
≤
100mA
LP295x-03 (±1%),
Note 14,
100µA
≤
I
L
≤
100mA
LP2951-4.8 (±1%),
Note 14,
100µA
≤
I
L
≤
100mA
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
20
50
50
0.03
0.04
0.04
0.04
0.10
0.10
Typ
5.000
5.000
4.850
Max
5.025
5.050
4.899
5.050
5.075
4.872
5.060
5.100
4.947
5.070
5.120
4.967
100
150
150
0.10
0.20
0.20
0.40
0.20
0.40
0.10
0.20
0.20
0.30
0.20
0.30
Units
V
V
V
V
V
V
V
V
V
V
V
V
ppm/°C
ppm/°C
ppm/°C
%
%
%
%
%
%
%
%
%
%
%
%
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Micrel, Inc.
LP2950/2951
Parameter
Dropout Voltage
Condition
Note 5,
I
L
= 100µA
Note 5,
I
L
= 100mA
Min
Typ
50
380
100
8
180
160
0.05
430
160
100
Max
80
150
450
600
150
200
12
14
250
310
220
220
0.20
Units
mV
mV
mV
mV
µA
µA
mA
mA
µA
µA
mA
mA
%/W
µV
RMS
µV
RMS
µV
RMS
Ground Current
I
L
= 100µA
I
L
= 100mA
Dropout Current
Current Limit
Thermal Regulation
Output Noise
V
IN
= 4.5V, I
L
= 100µA
V
OUT
= 0V
Note 13
10Hz to 100kHz, C
L
= 1µF
10Hz to 100kHz, C
L
= 200µF
10Hz to 100kHz, C
L
= 3.3µF,
0.01µF bypass Feedback to Output
Reference Voltage
LP295x-02 (±0.5%)
LP295x-03 (±1%)
LP2951-4.8 (±1%)
1.220
1.200
1.210
1.200
1.210
1.200
1.190
1.185
1.185
1.235
1.235
1.235
1.250
1.260
1.260
1.270
1.260
1.270
1.270
1.285
1.285
V
V
V
V
V
V
V
V
V
nA
nA
ppm/°C
ppm/°C
ppm/°C
nA/°C
Reference Voltage
LP295x-02 (±0.5%),
Note 7
LP295x-03 (±1%),
Note 7
LP2951-4.8 (±1%),
Note 7
Feedback Bias Current
Reference Voltage
LP295x-02 (±0.5%),
Note 12
LP295x-03 (±1%),
Note 12
LP2951-4.8 (±1%),
Note 12
Feedback Bias Current
Temperature Coefficient
Output Leakage Current
Output Low Voltage (Flag)
Upper Threshold Voltage
Lower Threshold Voltage
Hysteresis
V
OH
= 30V
V
IN
= 4.5V, I
OL
= 200µA
Note 6
Note 6
Note 6
40
25
20
20
50
50
0.1
0.01
150
60
75
15
40
60
1.00
2.00
250
400
µA
µA
mV
mV
mV
mV
95
140
mV
mV
mV
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LP2950/2951
Parameter
Input Logic Voltage
Condition
LP295x-02 (±0.5%)
Low
High
LP295x-03 (±1%)
Low
High
LP2951-4.8 (±1%)
Low
High
Min
Typ
1.3
Max
0.7
Units
V
V
V
V
V
V
V
V
V
µA
µA
µA
µA
µA
µA
2.0
1.3
0.7
2.0
1.3
0.7
2.0
30
450
3
50
100
600
700
10
20
Shutdown Input Current
V
SHUTDOWN
= 2.4V
V
SHUTDOWN
= 30V
Regulator Output Current
in Shutdown
Notes:
1.
2.
3.
4.
5.
Note 11
Boldface limits apply at temperature extremes.
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.
Guaranteed and 100% production tested.
Guaranteed but not 100% production tested. These limits are not used to calculate outgoing AQL levels.
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.
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
=(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 V
OUT
as V
OUT
is varied, with the dropout warning occurring at typically 5% below nominal, 7.5%
guaranteed.
V
REF
≤
V
OUT
≤
(V
IN
– 1 V), 2.3V
≤
V
IN
≤
30V, 100µA < I
L
≤
100mA, T
J
≤
T
JMAX
.
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.
May exceed input supply voltage.
6.
7.
8.
9.
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.
11. V
SHUTDOWN
≥
2V, V
IN
≤
30 V, V
OUT
= 0, with Feedback pin tied to 5V Tap.
12. Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
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 V
IN
= 30V (1.25W pulse) for t = 10ms.
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.
15. Line regulation for the LP2951 is tested at 150°C for I
L
= 1mA. For I
L
= 100µA 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.
September 2008
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M9999-091208
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