LP2951AMDC [TI]
FIXED/ADJUSTABLE POSITIVE LDO REGULATOR, 0.6V DROPOUT, UUC, DIE;
| 型号： | LP2951AMDC |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | FIXED/ADJUSTABLE POSITIVE LDO REGULATOR, 0.6V DROPOUT, UUC, DIE 输出元件 调节器 |
| 文件： | 总29页 (文件大小：806K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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information and details on our current products and services.
July 2000
LP2950/LP2951
Series of Adjustable Micropower Voltage Regulators
(.05% typ.) and a very low output voltage temperature coef-
ficient, making the part useful as a low-power voltage refer-
ence.
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.
Features
n 5V, 3V, and 3.3V versions available
n High accuracy output voltage
n Guaranteed 100 mA output current
n Extremely low quiescent current
n Low dropout voltage
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.
n Extremely tight load and line regulation
n Very low temperature coefficient
n Use as Regulator or Reference
n Needs minimum capacitance for stability
n Current and Thermal Limiting
n Stable with low-ESR output capacitors
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.
LP2951 versions only
n Error flag warns of output dropout
n Logic-controlled electronic shutdown
n Output programmable from 1.24 to 29V
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
Block Diagram and Typical Applications
LP2950
LP2951
DS008546-25
DS008546-1
© 2000 National Semiconductor Corporation
DS008546
www.national.com
Connection Diagrams
TO-92 Plastic Package (Z)
Dual-In-Line Packages (N, J)
Surface-Mount Package (M, MM)
DS008546-2
Bottom View
DS008546-26
Top View
Metal Can Package (H)
10-Lead Ceramic Surface-Mount Package (WG)
DS008546-64
Top View
DS008546-19
Top View
TO-252 (D-Pak)
DS008546-70
Front View
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2
Ordering Information
Package
Output Voltage
3.3V
Temperature
(˚C)
3.0V
5.0V
LP2950ACZ-5.0
LP2950CZ-5.0
LP2950CDT-5.0
LP2951ACN
LP2951CN
< <
−40 TJ 125
TO-92 (Z)
LP2950ACZ-3.0
LP2950CZ-3.0
LP2950CDT-3.0
LP2951ACN-3.0
LP2951CN-3.0
LP2951ACM-3.0
LP2951CM-3.0
LP2950ACZ-3.3
LP2950CZ-3.3
LP2950CDT-3.3
LP2951ACN-3.3
LP2951CN-3.3
LP2951ACM-3.3
LP2951CM-3.3
< <
−40 TJ 125
TO-252 (D-Pak)
N (N-08E)
<
<
−40 TJ 125
< <
−40 TJ 125
M (M08A)
LP2951ACM
LP2951CM
< <
−40 TJ 125
MM (MUA08A) in LP2951ACMM-3.0 LP2951ACMM-3.3 LP2951ACMM
Tape and Reel
LP2951CMM-3.0
LP2951CMM-3.3
LP2951CMM
LP2951ACJ
LP2951CJ
< <
−40 TJ 125
J (J08A)
< <
−55 TJ 150
LP2951J
LP2951J/883
5926-3870501MPA
LP2951H/883
< <
−55 TJ 150
H (H08C)
5962-3870501MGA
LP2951WG/883
5962-3870501MXA
< <
−55 TJ 150
WG (WG10A)
Package Marking for MM Package:
Order Number
Package Marking
LP2951ACMM
L0DA
L0DB
L0CA
L0CB
L0BA
L0BB
LP2951CMM
LP2951ACMM-3.3
LP2951CMM-3.3
LP2951ACMM-3.0
LP2951CMM-3.0
3
www.national.com
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Soldering Dwell Time, Temperature
Wave
4 seconds, 260˚C
10 seconds, 240˚C
75 seconds, 219˚C
Infrared
Vapor Phase
ESD
TBD
Input Supply Voltage
−0.3 to +30V
Operating Ratings (Note 1)
SHUTDOWN Input Voltage,
Error Comparator Output
Voltage, (Note 9)
Maximum Input Supply Voltage
30V
Junction Temperature Range
(TJ) (Note 8)
FEEDBACK Input Voltage
(Note 9) (Note 10)
−1.5 to +30V
LP2951
−55˚ to +150˚C
−40˚ to +125˚C
Power Dissipation
Internally Limited
+150˚C
LP2950AC-XX, LP2950C-XX,
LP2951AC-XX, LP2951C-XX
Junction Temperature (TJ)
Ambient Storage Temperature
−65˚ to +150˚C
Electrical Characteristics (Note 2)
LP2951
LP2950AC-XX
LP2951AC-XX
LP2950C-XX
LP2951C-XX
Conditions
Parameter
Tested
Tested
Limit
Design
Limit
Tested
Limit
Design
Limit
Units
(Note 2)
Typ
Limit
Typ
Typ
(Notes 3, 16)
(Note 3) (Note 4)
(Note 3) (Note 4)
3V VERSIONS (Note 17)
Output Voltage
TJ = 25˚C
3.0
3.0
3.0
3.0
3.015
2.985
3.0
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
−25˚C ≤ TJ ≤ 85˚C
Full Operating
3.036
2.964
3.045
2.955
Temperature Range
100 µA ≤ IL ≤ 100 mA
TJ ≤ TJMAX
Output Voltage
3.3V VERSIONS (Note 17)
Output Voltage
TJ = 25˚C
3.3
3.3
3.3
3.3
3.317
3.284
3.3
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
−25˚C ≤ TJ ≤ 85˚C
Full Operating
3.340
3.260
3.350
3.251
Temperature Range
100 µA ≤ IL ≤ 100 mA
TJ ≤ TJMAX
Output Voltage
5V VERSIONS (Note 17)
Output Voltage
TJ = 25˚C
5.0
5.0
5.0
5.0
5.025
4.975
5.0
5.0
5.0
5.0
5.025
4.975
5.05
5.0
5.0
5.0
5.0
5.05
4.95
5.075
4.925
5.1
V max
V min
V max
V min
V max
V min
V max
V min
−25˚C ≤ TJ ≤ 85˚C
4.95
Full Operating
5.06
4.94
5.06
Temperature Range
100 µA ≤ IL ≤ 100 mA
TJ ≤ TJMAX
4.94
4.9
Output Voltage
5.075
4.925
5.075
4.925
5.12
4.88
ALL VOLTAGE OPTIONS
Output Voltage
Temperature Coefficient
(Note 12)
20
120
20
100
50
150
ppm/˚C
Line Regulation
(Note 14)
(VONOM + 1)V ≤ Vin ≤ 30V 0.03
0.1
0.5
0.1
0.3
0.03
0.1
0.2
0.1
0.2
0.04
0.2
0.4
0.2
0.3
% max
% max
% max
% max
(Note 15)
Load Regulation
(Note 14)
100 µA ≤ IL ≤ 100 mA
0.04
0.04
0.1
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4
Electrical Characteristics (Note 2) (Continued)
LP2951
LP2950AC-XX
LP2951AC-XX
LP2950C-XX
LP2951C-XX
Conditions
Parameter
Tested
Limit
Tested
Limit
Design
Limit
Tested
Limit
Design
Limit
Units
(Note 2)
Typ
Typ
Typ
(Notes 3, 16)
(Note 3) (Note 4)
(Note 3) (Note 4)
ALL VOLTAGE OPTIONS
Dropout Voltage
(Note 5)
IL = 100 µA
80
80
80
mV max
mV max
mV max
mV max
µA max
µA max
mA max
mA max
µA max
µA max
mA max
mA max
%/W max
µV rms
50
150
450
600
120
140
12
50
150
450
600
120
140
12
50
150
450
600
120
140
12
IL = 100 mA
IL = 100 µA
IL = 100 mA
380
75
380
75
380
75
Ground
Current
8
8
8
14
14
14
Dropout
Vin = (VONOM − 0.5)V
IL = 100 µA
110
160
170
200
200
220
0.2
110
160
170
200
200
220
0.2
110
160
170
200
200
220
0.2
Ground Current
Current Limit
Vout = 0
Thermal Regulation
Output Noise,
(Note 13)
0.05
430
160
0.05
430
160
0.05
430
160
CL = 1 µF (5V Only)
CL = 200 µF
10 Hz to 100 kHz
µV rms
CL = 3.3 µF
(Bypass = 0.01 µF
Pins 7 to 1 (LP2951))
100
100
100
µV rms
8-PIN VERSIONS ONLY
Reference
LP2951
1.25
1.26
1.22
1.2
LP2951AC-XX
LP2951C-XX
1.26
1.235
1.235
1.25
1.26
1.22
1.2
1.235
V max
V max
V min
Voltage
1.27
1.21
1.2
V min
Reference
(Note 7)
1.27
1.19
40
1.27
1.19
40
1.285
1.185
40
V max
V min
Voltage
Feedback Pin
Bias Current
Reference Voltage
Temperature Coefficient
Feedback Pin Bias
Current Temperature
Coefficient
20
20
20
20
20
50
nA max
nA max
ppm/˚C
60
60
60
(Note 12)
0.1
0.1
0.1
nA/˚C
Error Comparator
Output Leakage
Current
VOH = 30V
0.01
150
60
1
0.01
150
60
1
0.01
150
60
1
µA max
µA max
mV max
mV max
mV min
mV min
mV max
mV max
mV
2
2
2
Output Low
Vin = (VONOM − 0.5)V
IOL = 400 µA
250
400
40
250
400
40
250
400
40
Voltage
Upper Threshold
Voltage
(Note 6)
25
25
25
Lower Threshold
Voltage
(Note 6)
(Note 6)
75
95
75
95
75
95
140
140
140
Hysteresis
15
15
15
Shutdown Input
Input
1.3
1.3
1.3
V
Logic
Low (Regulator ON)
High (Regulator OFF)
0.6
2.0
0.7
2.0
0.7
2.0
V max
V min
Voltage
5
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Electrical Characteristics (Note 2) (Continued)
LP2951
LP2950AC-XX
LP2951AC-XX
LP2950C-XX
LP2951C-XX
Conditions
Parameter
Tested
Limit
Tested
Limit
Design
Limit
Tested
Limit
Design
Limit
Units
(Note 2)
Typ
Typ
Typ
(Notes 3, 16)
(Note 3) (Note 4)
(Note 3) (Note 4)
Shutdown Input
Shutdown Pin Input
Current
Vshutdown = 2.4V
Vshutdown = 30V
(Note 11)
30
450
3
50
100
600
750
10
30
450
3
50
100
600
750
10
30
450
3
50
100
600
750
10
µA max
µA max
µA max
µA max
µA max
µA max
Regulator Output
Current in Shutdown
20
20
20
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device
is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical
Characteristics tables.
Note 2: Unless otherwise specified all limits guaranteed for V = (V
+ 1)V, I = 100 µA and C = 1 µF for 5V versions and 2.2 µF for 3V and 3.3V versions.
L L
IN
ONOM
Limits appearing in boldface type apply over the entire junction temperature range for operation. Limits appearing in normal type apply for T = T = 25˚C. Additional
A
J
conditions for the 8-pin versions are FEEDBACK tied to V
, OUTPUT tied to SENSE, and V
≤ 0.8V.
SHUTDOWN
TAP
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 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: Comparator thresholds are expressed in terms of a voltage differential at the Feedback terminal below the nominal reference voltage measured at
V
= (V NOM + 1)V. To express these thresholds in terms of output voltage change, multiply by the error amplifier gain = V /V = (R1 + R2)/R2.
O out ref
in
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/1.235V = 384 mV.
Thresholds remain constant as a percent of V as V is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed.
out
out
Note 7: V ≤ V ≤ (V − 1V), 2.3V ≤ V ≤ 30V, 100 µA ≤ I ≤ 100 mA, T ≤ T .
JMAX
ref
out
in
in
L
J
Note 8: The junction-to-ambient thermal resistances are as follows: 180˚C/W and 160˚C/W for the TO-92 package with 0.40 inch and 0.25 inch leads to the printed
circuit board (PCB) respectively, 105˚C/W for the molded plastic DIP (N), 130˚C/W for the ceramic DIP (J), 160˚C/W for the molded plastic SOP (M), 200˚C/W for the
molded plastic MSOP (MM), and 160˚C/W for the metal can package (H). The above thermal resistances for the N, J, M, and MM packages apply when the package
is soldered directly to the PCB. Junction-to-case thermal resistance for the H package is 20˚C/W. Junction-to-case thermal resistance for the TO-252 package is
5.4˚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: V
≥ 2V, V ≤ 30V, V
= 0, Feedback pin tied to V
.
TAP
shutdown
in
out
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 50 mA load pulse at V = 30V (1.25W pulse) for T = 10 ms.
IN
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 under the specification for thermal regulation.
Note 15: Line regulation for the LP2951 is tested at 150˚C for I = 1 mA. For I = 100 µA and T = 125˚C, line regulation is guaranteed by design to 0.2%. See Typical
L
L
J
Performance Characteristics for line regulation versus temperature and load current.
Note 16: A Military RETS specification is available on request. At time of printing, the LP2951 RETS specification complied with the boldface limits in this column.
The LP2951H, WG, or J may also be procured as Standard Military Drawing Spec #5962-3870501MGA, MXA, or MPA.
Note 17: All LP2950 devices have the nominal output voltage coded as the last two digits of the part number. In the LP2951 products, the 3.0V and 3.3V versions
are designated by the last two digits, but the 5V version is denoted with no code at this location of the part number (refer to ordering information table).
Typical Performance Characteristics
Quiescent Current
Dropout Characteristics
Input Current
DS008546-27
DS008546-28
DS008546-29
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6
Typical Performance Characteristics (Continued)
Input Current
Output Voltage vs.
Temperature of 3
Quiescent Current
Representative Units
DS008546-30
DS008546-32
DS008546-31
DS008546-34
DS008546-37
Quiescent Current
Quiescent Current
Quiescent Current
DS008546-33
DS008546-35
Short Circuit Current
Dropout Voltage
Dropout Voltage
DS008546-38
DS008546-36
7
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Typical Performance Characteristics (Continued)
LP2951
Minimum Operating Voltage
LP2951
Feedback Bias Current
LP2951
Feedback Pin Current
DS008546-39
DS008546-40
DS008546-41
LP2951
Error Comparator Output
LP2951
Comparator Sink Current
Line Transient Response
DS008546-44
DS008546-42
DS008546-43
Load Transient Response
Load Transient Response
LP2951
Enable Transient
DS008546-45
DS008546-46
DS008546-47
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8
Typical Performance Characteristics (Continued)
Output Impedance
Ripple Rejection
Ripple Rejection
DS008546-48
DS008546-49
DS008546-50
Ripple Rejection
LP2951 Output Noise
LP2951 Divider Resistance
DS008546-51
DS008546-52
DS008546-53
Shutdown Threshold Voltage
Line Regulation
LP2951 Maximum
Rated Output Current
DS008546-54
DS008546-55
DS008546-56
LP2950 Maximum
Rated Output Current
Thermal Response
Output Capacitor ESR Range
DS008546-58
DS008546-57
DS008546-63
9
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Application Hints
EXTERNAL CAPACITORS
sistor, note that while the output is rated to sink 400 µA, this
sink current adds to battery drain in a low battery condition.
Suggested values range from 100k to 1 MΩ. The resistor is
not required if this output is unused.
A 1.0 µF (or greater) capacitor is required between the out-
put and ground for stability at output voltages of 5V or more.
At lower output voltages, more capacitance is required
(2.2 µF or more is recommended for 3V and 3.3V versions).
Without this capacitor the part will oscillate. Most types of
tantalum or aluminum electrolytics work fine here; even film
types work but are not recommended for reasons of cost.
Many aluminum electrolytics have electrolytes that freeze at
about −30˚C, so solid tantalums are recommended for op-
eration below −25˚C. The important parameters of the ca-
pacitor are an ESR of about 5 Ω or less and a resonant fre-
quency above 500 kHz. The value of this capacitor may be
increased without limit.
At lower values of output current, less output capacitance is
required for stability. The capacitor can be reduced to
0.33 µF for currents below 10 mA or 0.1 µF for currents be-
low 1 mA. Using the adjustable versions at voltages below
5V runs the error amplifier at lower gains so that more output
capacitance is needed. For the worst-case situation of a
100 mA load at 1.23V output (Output shorted to Feedback) a
3.3 µF (or greater) capacitor should be used.
DS008546-20
*
When V ≤ 1.3V, the error flag pin becomes a high impedance, and the
IN
error flag voltage rises to its pull-up voltage. Using V
as the pull-up
OUT
voltage (see Figure 2), rather than an external 5V source, will keep the
error flag voltage under 1.2V (typ.) in this condition. The user may wish to
divide down the error flag voltage using equal-value resistors (10 kΩ
suggested), to ensure a low-level logic signal during any fault condition,
while still allowing a valid high logic level during normal operation.
Unlike many other regulators, the LP2950 will remain stable
and in regulation with no load in addition to the internal volt-
age divider. This is especially important in CMOS RAM
keep-alive applications. When setting the output voltage of
the LP2951 versions with external resistors, a minimum load
of 1 µA is recommended.
FIGURE 1. ERROR Output Timing
PROGRAMMING THE OUTPUT VOLTAGE (LP2951)
The LP2951 may be pin-strapped for the nominal fixed out-
put voltage using its internal voltage divider by tying the out-
put and sense pins together, and also tying the feedback and
VTAP pins together. Alternatively, it may be programmed for
any output voltage between its 1.235V reference and its 30V
maximum rating. As seen in Figure 2, an external pair of re-
sistors is required.
A 1 µF tantalum or aluminum electrolytic capacitor should be
placed from the LP2950/LP2951 input to ground if there is
more than 10 inches of wire between the input and the AC fil-
ter capacitor or if a battery is used as the input.
The complete equation for the output voltage is
Stray capacitance to the LP2951 Feedback terminal can
cause instability. This may especially be a problem when us-
ing high value external resistors to set the output voltage.
Adding a 100 pF capacitor between Output and Feedback
and increasing the output capacitor to at least 3.3 µF will fix
this problem.
where VREF is the nominal 1.235 reference voltage and IFB is
the feedback pin bias current, nominally −20 nA. The mini-
mum recommended load current of 1 µA forces an upper
limit of 1.2 MΩ on the value of R2, if the regulator must work
with no load (a condition often found in CMOS in standby).
IFB will produce a 2% typical error in VOUT which may be
eliminated at room temperature by trimming R1. For better
accuracy, choosing R2 = 100k reduces this error to 0.17%
while increasing the resistor program current to 12 µA. Since
the LP2951 typically draws 60 µA at no load with Pin 2
open-circuited, this is a small price to pay.
ERROR DETECTION COMPARATOR OUTPUT
The comparator produces a logic low output whenever the
LP2951 output falls out of regulation by more than approxi-
mately 5%. This figure is the comparator’s built-in offset of
about 60 mV divided by the 1.235 reference voltage. (Refer
to the block diagram in the front of the datasheet.) This trip
level remains “5% below normal” regardless of the pro-
grammed output voltage of the 2951. For example, the error
flag trip level is typically 4.75V for a 5V output or 11.4V for a
12V output. The out of regulation condition may be due ei-
ther to low input voltage, current limiting, or thermal limiting.
Figure 1 below gives a timing diagram depicting the ERROR
signal and the regulated output voltage as the LP2951 input
is ramped up and down. For 5V versions, the ERROR signal
becomes valid (low) at about 1.3V input. It goes high at
about 5V input (the input voltage at which VOUT = 4.75V).
Since the LP2951’s dropout voltage is load-dependent (see
curve in typical performance characteristics), the input volt-
age trip point (about 5V) will vary with the load current. The
output voltage trip point (approx. 4.75V) does not vary with
load.
The error comparator has an open-collector output which re-
quires an external pullup resistor. This resistor may be re-
turned to the output or some other supply voltage depending
on system requirements. In determining a value for this re-
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10
Application Hints (Continued)
DS008546-7
*
See Application Hints
**
Drive with TTL-high to shut down. Ground or leave open if shutdown
feature is not to be used.
Note: Pins 2 and 6 are left open.
FIGURE 2. Adjustable Regulator
REDUCING OUTPUT NOISE
In reference applications it may be advantageous to reduce
the AC noise present at the output. One method is to reduce
the regulator bandwidth by increasing the size of the output
capacitor. This is the only way noise can be reduced on the
3 lead LP2950 but is relatively inefficient, as increasing the
capacitor from 1 µF to 220 µF only decreases the noise from
430 µV to 160 µV rms for a 100 kHz bandwidth at 5V output.
Noise can be reduced fourfold by a bypass capacitor across
R1, since it reduces the high frequency gain from 4 to unity.
Pick
or about 0.01 µF. When doing this, the output capacitor must
be increased to 3.3 µF to maintain stability. These changes
reduce the output noise from 430 µV to 100 µV rms for a
100 kHz bandwidth at 5V output. With the bypass capacitor
added, noise no longer scales with output voltage so that im-
provements are more dramatic at higher output voltages.
11
www.national.com
Typical Applications
1A Regulator with 1.2V Dropout
DS008546-22
300 mA Regulator with 0.75V Dropout
Wide Input Voltage Range Current Limiter
DS008546-9
DS008546-21
*
Minimum input-output voltage ranges from 40 mV to 400 mV, depending
on load current. Current limit is typically 160 mA.
Low Drift Current Source
5 Volt Current Limiter
DS008546-10
*
Minimum input-output voltage ranges from 40 mV to 400 mV, depending
on load current. Current limit is typically 160 mA.
DS008546-8
www.national.com
12
Typical Applications (Continued)
Regulator with Early Warning and Auxiliary Output
Latch Off When Error Flag Occurs
DS008546-12
DS008546-11
j
j
j
Early warning flag on low input voltage
Main output latches off at lower input voltages
Battery backup on auxiliary output
Operation: Reg. #1’s V is programmed one diode drop above 5V. Its
out
error flag becomes active when V ≤ 5.7V. When V drops below 5.3V,
in
in
the error flag of Reg. #2 becomes active and via Q1 latches the main
output off. When V again exceeds 5.7V Reg. #1 is back in regulation and
in
the early warning signal rises, unlatching Reg. #2 via D3.
13
www.national.com
Typical Applications (Continued)
2 Ampere Low Dropout Regulator
DS008546-13
For 5V , use internal resistors. Wire pin 6 to 7, & wire pin 2 to +V Bus.
out
out
→
5V Regulator with 2.5V Sleep Function
Open Circuit Detector for 4
20 mA Current Loop
DS008546-15
DS008546-14
*
High input lowers V to 2.5V
out
www.national.com
14
Typical Applications (Continued)
Regulator with State-of-Charge Indicator
DS008546-16
*
Optional Latch off when drop out occurs. Adjust R3 for C2 Switching when V is 6.0V.
in
**
Outputs go low when V drops below designated thresholds.
in
Low Battery Disconnect
DS008546-17
<
For values shown, Regulator shuts down when V
5.5V and turns on again at 6.0V. Current drain in disconnected mode is ≈ 150 µA.
in
*
Sets disconnect Voltage
**
Sets disconnect Hysteresis
15
www.national.com
Typical Applications (Continued)
System Overtemperature Protection Circuit
DS008546-18
LM34 for 125˚F Shutdown
LM35 for 125˚C Shutdown
www.national.com
16
Schematic Diagram
17
www.national.com
Physical Dimensions inches (millimeters) unless otherwise noted
Order Number LP2951WG/883 or 5962-3870501MXA
NS Package Number WG10A
Metal Can Package (H)
Order Number LP2951H/883 or 5962-3870501MGA
NS Package Number H08C
www.national.com
18
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Ceramic Dual-In-Line Package (J)
Order Number LP2951CJ, LP2951ACJ, LP2951J, LP2951J/883 or 5962-3870501MPA
NS Package Number J08A
Surface Mount Package (M)
Order Number LP2951ACM, LP2951CM, LP2951ACM-3.0,
LP2951CM-3.0, LP2951ACM-3.3 or LP2951CM-3.3
NS Package Number M08A
19
www.national.com
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Molded Dual-In-Line Package (N)
Order Number LP2951ACN, LP2951CN, LP2951ACN-3.0,
LP2951CN-3.0, or LP2951ACN-3.3 or LP2951CN-3.3
NS Package Number N08E
Molded TO-92 Package (Z)
Order Number LP2950ACZ-3.0 or LP2950CZ-3.0, LP2950ACZ-3.3,
LP2950CZ-3.3, LP2950ACZ-5.0 or LP2950CZ-5.0
NS Package Number Z03A
www.national.com
20
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Surface Mount Package (MM)
Order Number LP2951ACMM, LP2951CMM, LP2951ACMM-3.0,
LP2951CMM-3.0, LP2951ACMM-3.3 or LP2951CMM-3.3
NS Package Number MUA08A
D-Pak Package
Order Number LP2950CDT-3.0, LP2950CDT-3.3, or LP2950CDT-5.0
NS Package Number TD03B
21
www.national.com
Notes
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
National Semiconductor
Corporation
Americas
Tel: 1-800-272-9959
Fax: 1-800-737-7018
Email: support@nsc.com
National Semiconductor
Europe
National Semiconductor
Asia Pacific Customer
Response Group
Tel: 65-2544466
Fax: 65-2504466
National Semiconductor
Japan Ltd.
Tel: 81-3-5639-7560
Fax: 81-3-5639-7507
Fax: +49 (0) 180-530 85 86
Email: europe.support@nsc.com
Deutsch Tel: +49 (0) 69 9508 6208
English Tel: +44 (0) 870 24 0 2171
Français Tel: +33 (0) 1 41 91 8790
Email: ap.support@nsc.com
www.national.com
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.
See A/D Converters
Products
Products > Analog - Regulators > Linear Regulators - Low Dropout Voltage > Positive Voltage - Adjustable
> LP2951
LP2951 Product Folder
Series of Adjustable Micropower Voltage Regulators
Generic P/N 2951
General
Description
Package
& Models
Samples
& Pricing
Application
Notes
Features
Datasheet
Parametric Table
Multiple Output Capability
On/Off Pin
Parametric Table
No
Dropout Voltage, typ (Volt)
Quiescent Current, typ (mA)
Secondary Ouput Voltage (Volt)
Secondary Output Current (Amp)
Output Voltage, min (Volt)
Output Voltage, max (Volt)
Watchdog
.38
Yes
.0750
Error Flag
Yes
-
Input Voltage, min (Volt)
Input Voltage, max (Volt)
Output Current, max
-.30
30
-
1.24, 1.2350
29, 29.50
No
100 mA
Datasheet
Size in
Kbytes
Title
Date
Receive via
Email
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View Online
14-
Jul-
00
Receive via
Email
LP2950 LP2951 Series of Adjustable Micropower Voltage 657
View Online Download
Regulators
Kbytes
LP2950 LP2951 Series of Adjustable Micropower Voltage
Regulators (JAPANESE)
704
Kbytes
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Receive via
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Email
268
Kbytes
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LP2951 Mil-Aero (JAN) Datasheet MJLP2951-X
LP2951 Mil-Aero Datasheet MNLP2951-X
Receive via
Email
267
Kbytes
If you have trouble printing or viewing PDF file(s), see Printing Problems.
Package Availability, Models, Samples & Pricing
Budgetary
Pricing
Samples &
Electronic
Orders
Std
Pack
Size
Package
Models
Package
Marking
Part Number
Status
Type Pins MSL
SPICE IBIS
Qty $US each
24 Hour
rail
of
95
[logo]¢2¢T
2951
ACM¢D
SOIC
NARROW
Full
production
MSL
MSL
MSL
MSL
MSL
MSL
LP2951ACM
8
8
8
8
8
8
N/A
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N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
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1K+ $0.3100
1K+ $0.3100
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1K+ $0.2800
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1K+ $0.2800
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24 Hour
rail
of
95
[logo]¢2¢T
2951A
CM30¢D
SOIC
NARROW
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production
LP2951ACM-3.0
LP2951ACM-3.3
LP2951CM
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Samples
rail
of
95
[logo]¢2¢T
2951A
CM33¢D
SOIC
NARROW
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production
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24 Hour
rail
of
95
[logo]¢2¢T
2951
SOIC
NARROW
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production
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CM¢D
24 Hour
rail
of
95
[logo]¢2¢T
2951C
M30¢D
SOIC
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production
LP2951CM-3.0
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24 Hour
rail
of
95
[logo]¢2¢T
2951C
M33¢D
SOIC
NARROW
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LP2951CM-3.3
LP2951ACMX
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reel
of
2500
[logo]¢2¢T
2951
ACM¢D
SOIC
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production
MSL
MSL
MSL
MSL
MSL
MSL
8
8
8
8
8
8
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
1K+ $0.3100
1K+ $0.3100
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1K+ $0.2800
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reel
of
2500
[logo]¢2¢T
2951A
CM30¢D
SOIC
NARROW
LP2951ACMX-
3.0
Full
production
reel
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2500
[logo]¢2¢T
2951A
CM33¢D
SOIC
NARROW
LP2951ACMX-
3.3
Full
production
reel
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2500
[logo]¢2¢T
2951
SOIC
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production
LP2951CMX
CM¢D
reel
of
2500
[logo]¢2¢T
2951C
M30¢D
SOIC
NARROW
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production
LP2951CMX-3.0
LP2951CMX-3.3
reel
of
2500
[logo]¢2¢T
2951C
M33¢D
SOIC
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production
Samples
reel
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1000
MINI
SOIC
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production
¢Z¢1¢T
L0DA
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MSL
LP2951ACMM
8
8
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1K+ $0.3980
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reel
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1000
MINI
SOIC
LP2951ACMM-
3.0
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¢Z¢1¢T
L0BA
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1000
MINI
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LP2951ACMM-
3.3
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L0CA
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MINI
SOIC
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¢Z¢1¢T
L0DB
MSL
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LP2951CMM
8
8
8
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N/A
1K+ $0.3650
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Samples
reel
of
1000
MINI
SOIC
LP2951CMM-
3.0
Full
production
¢Z¢1¢T
L0BB
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reel
of
1000
MINI
SOIC
LP2951CMM-
3.3
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¢Z¢1¢T
L0CB
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reel
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3500
MINI
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¢Z¢1¢T
L0DA
MSL
MSL
MSL
MSL
MSL
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LP2951ACMMX
8
8
8
8
8
8
N/A
N/A
N/A
N/A
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1K+ $0.3980
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1K+ $0.3650
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reel
of
3500
MINI
SOIC
LP2951ACMMX-
3.0
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¢Z¢1¢T
L0BA
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LP2951ACMMX-
3.3
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¢Z¢1¢T
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LP2951CMMX
reel
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3500
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LP2951CMMX-
3.0
Full
production
¢Z¢1¢T
L0BB
reel
of
3500
MINI
SOIC
LP2951CMMX-
3.3
Full
production
¢Z¢1¢T
L0CB
24 Hour
rail
of
40
[logo]¢U¢Z¢2¢T
LP
Full
production
MDIP
MDIP
MDIP
MSL
MSL
MSL
LP2951ACN
8
8
8
N/A
N/A
N/A
N/A
N/A
N/A
1K+ $0.3400
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2951ACN
rail
of
40
[logo]¢U¢Z¢2¢T
LP2951
Full
production
LP2951ACN-3.0
LP2951ACN-3.3
ACN-3.0
24 Hour
rail
of
40
[logo]¢U¢Z¢2¢T
LP2951
Full
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ACN-3.3
24 Hour
rail
of
40
[logo]¢U¢Z¢2¢T
Full
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MDIP
MDIP
MDIP
LCC
MSL
MSL
MSL
MSL
LP2951CN
8
8
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N/A
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25+ $24.2000
LP
2951CN
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rail
of
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[logo]¢U¢Z¢2¢T
LP2951
Full
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LP2951CN-3.0
LP2951CN-3.3
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24 Hour
rail
of
40
[logo]¢U¢Z¢2¢T
LP2951
Full
production
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CN-3.3
[logo]¢Z¢S¢4¢A
LP2951E/883
Q¢M$E 5962-
3870501M2A
rail
of
50
5962-
3870501M2A
Full
production
20
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[logo] ¢Z¢S¢4¢A
LP2951H/883Q¢M
5962-
tray
of
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5962-
3870501MGA
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TO-5
MSL
MSL
8
8
N/A
N/A
N/A
N/A
25+ $22.8000
25+ $13.7000
3870501MGA $E
[logo]¢Z¢S¢4¢A$E
LP2951J/883
Q 5962-
rail
of
40
5962-
3870501MPA
Full
production
CERDIP
3870501MPA
[logo] $E
¢Z¢S¢4¢A
LP2951WG
/Q5962-38
70501MXA
tray
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3870501MXA
Ceramic
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25+ $16.9000
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tray
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20
Full
production
[logo]¢Z¢S¢4¢A$E
LP2951H-MCP
TO-5
MSL
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LP2951H-MCP
8
8
N/A
N/A
N/A
N/A
250+ $8.3500
50+ $35.2000
[logo] 5962-
3870501BPA
27014 Q
rail
of
40
5962-
3870501BPA
Full
production
CERDIP
¢Z¢S¢4¢A$E
[logo]¢Z¢S¢4¢A
27014 Q¢M$E
5962-
rail
5962-
3870501S2A
Full
production
LCC
MSL
MSL
MSL
20
8
N/A
N/A
N/A
N/A
50+ $225.0000 of
50
3870501S2A
[logo]¢Z¢S¢4¢A$E
RM2951JX
QMLV WAFER#
¢R
rail
of
N/A
CERDIP
CERDIP
RM2951JXQMLV
Preliminary N/A
[logo]¢Z¢S¢4¢A$E
27014 Q
rail
50+ $207.0000 of
40
5962-
3870501SPA
Full
N/A
8
production
5962-
3870501SPA
tray
of
N/A
Full
N/A
Samples
Samples
Samples
Samples
Die
LP2951C MDC
N/A
N/A
N/A
N/A
-
-
-
-
production
tray
of
N/A
LP2951C-3.3
MDC
Full
N/A
Die
Die
Die
production
tray
of
N/A
Full
N/A
LP2951A MDC
production
tray
of
N/A
LP2951A-3.3
MDC
Full
N/A
production
wafer
jar
of
Full
N/A
Wafer
Wafer
Wafer
LP2951A MWC
N/A
N/A
N/A
-
-
-
production
N/A
wafer
jar
of
LP2951A-3.3
MWC
Full
N/A
production
N/A
wafer
jar
of
Full
N/A
LP2951C MWC
production
N/A
wafer
jar
of
LP2951C-3.3
MWC
Full
production
Wafer
N/A
N/A
-
N/A
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
resistors.
Careful design of the LP2950/LP2951 has minimized all contributions to the error budget. This includes a
tight initial tolerance (.5% typ.), extremely good load and line regulation (.05% typ.) and a very low output
voltage temperature coefficient, making the part useful as a low-power voltage reference.
Features
●
●
●
●
●
●
●
●
●
●
●
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
Application Notes
Title
Size in Kbytes Date
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AN-853: Power Fail Circuit-
Working with NS32FX200
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67 Kbytes
5-Aug-95
AN-908: Specification for the
DECT ARi Interface to the Radio
Frequency Front End
143 Kbytes
5-Aug-95
5-Aug-95
AN-893: Using External Oscillators
for the DP857X Real Time Clocks
with the Battery Backed Mode
Selection
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73 Kbytes
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[Information as of 5-Aug-2002]
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