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National Linear Regulators & Low Dropout (LDO) Regulators
National Semiconductor's broad portfolio of low-noise, low-power low dropout (LDO) regulators preserve signal fidelity in the analog signal path over a wide range of input voltages and output currents. National's LDOs are offered in a variety of packages from the industry standard SOIC to LLP and Micro SMD to achieve the smallest footprint or the TO-263 for best thermal dissipation. Most of National's newer LDOs are supported by National's award-winning WEBENCH® tools.
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LP3878 Very Low Noise Micropower LDO
"800 mA Low Noise "Ceramic Stable" Adjustable Voltage Regulator for 1V to 5V applications. The LP3878 features:
- Very low output noise (18 μV typ with 10 nF bypass capacitor)
- 1.0V to 5.5V output
- Designed for use with low ESR ceramic capacitors
- 8 Lead PSOP and LLP surface mount package
- <10 μA quiescent current in shutdown
- product information
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Linear/LDO Regulator Design Resources |
System Design
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Packaging & PCB Layout
- AN-1520 - A Guide to Board Layout for Best Thermal Resistance for Exposed Pad Packages (e.g. TO-263)
- AN-1797 - TO-263 THIN Package
LDO Fundamentals
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Low Noise LDOs for Low-Power, Space-Constrained Applications
These specially designed LDOs provide maximum PSRR (Power Supply Rejection Ratio) and low output voltage noise for low-power, space-constrained applications. ADCs, gigabit transceivers, PLLs, RF subsystems and other analog circuits are just some examples where power supply noise adversely affects performance. For more information, refer to App Note: Using Power to Improve Signal-Path Performance.
| Product ID |
Output Current (mA) |
Input Max Voltage (V) |
Input Min Voltage (V) |
Dropout Voltage (V) |
Output Voltage (V) |
Adjustable Output |
On/Off Pin |
Quiescent Current (mA) |
PSRR (dB) |
Voltage Noise (µV rms) |
|
150 |
5.5 |
2.5 |
0.08 |
1.5, 2.8, 3.3 |
— |
— |
0.025 |
75 |
6.5 |
|
200 |
5.5 |
2.2 |
0.15 |
1.8, 2.5, 2.6, 2.8, 2.85, 3.0, 3.1, 3.2 |
— |
— |
0.0325 |
75 |
10 |
|
800 |
6 |
2.5 |
— |
1.2, 1 |
— |
Y |
0.1 |
60 |
18 |
|
800 |
16 |
2.5 |
0.475 |
1 to 5.5V |
Y |
Y |
0.18 |
60 |
18 |
|
150 |
6 |
2.5 |
0.06 |
3, 2.8, 1.9 |
— |
— |
0.085 |
60 |
25 |
|
150 |
6 |
2.5 |
0.06 |
1.5, 2.4, 1.8, 2.5, 2.8, 3.3 |
— |
— |
0.085 |
60 |
30 |
|
200 |
5.5 |
2.2 |
0.15 |
0.8 to 3.6 |
— |
— |
0.03 |
55 |
60 |
|
250 |
6 |
2 |
0.14 |
3.3 |
— |
— |
0.055 |
61 |
100 |
|
800 |
7 |
2.5 |
0.24 |
5, 1.8, 2.5, 3.3 |
Y |
Y |
6 |
73 |
150 |
|
1500 |
7 |
2.5 |
0.38 |
5, 1.8, 2.5, 3.3 |
Y |
Y |
6 |
73 |
150 |
|
3000 |
7 |
2.5 |
0.8 |
5, 1.8, 2.5, 3.3 |
Y |
Y |
6 |
73 |
150 |
Low Input / Low Output LDOs
These LDOs have low dropout voltages and support low input voltages for highest efficiency. Especially useful when powering digital circuitry, these provide an easy-to-use power supply solution with minimal complexity, cost, and footprint. For more information, refer to How to power sub-micron CMOS loads with an efficient LDO (EETimes) and AN-1797: TO-263 THIN Package.
| Product ID |
Output Current (mA) |
Input Max Voltage (V) |
Input Min Voltage (V) |
Dropout Voltage (V) |
Output Voltage (V) |
On/Off Pin |
Package |
|
800 |
5.5 |
2.25 |
0.25 |
1.8, Adj |
Y |
TO263 Thin, PSOP |
|
800 |
5.5 |
0.915 |
0.115 |
Adjustable |
Y |
TO263, TO-220, PSOP |
|
1500 |
5.5 |
2.25 |
0.3 |
1.8, Adj |
Y |
TO263 Thin, PSOP |
|
1500 |
5.5 |
0.93 |
0.13 |
Adjustable |
Y |
TO263, TO-220, PSOP |
|
1500 |
5.5 |
0.98, 1.38 |
0.13 |
0.8, 1.2 |
Y |
TO263, TO-220 |
|
1500 |
5.5 |
0.98, 1.38 |
0.18 |
0.8, 1.2 |
N |
TO263, TO-220 |
|
3000 |
5.5 |
2.25 |
0.425 |
1.8, Adj |
Y |
TO263 Thin, PSOP |
|
3000 |
5.5 |
1.04 |
0.24 |
Adjustable |
Y |
TO263, TO-220, PSOP |
|
3000 |
5.5 |
1.15, 1.55 |
0.24 |
0.8, 1.2 |
Y |
TO263, TO-220 |
|
3000 |
5.5 |
1.15, 1.55 |
0.24 |
0.8, 1.2 |
N |
TO263, TO-220 |
|
150 |
6 |
2 |
0.06 |
1.5, 3.8, 1.8, 2.5, 0.8, 1.35, 2.8, 1.2, 3.3 |
Y |
SOT23-5, micro SMD-4, LLP-6 |
|
350 |
4.5 |
0.9 |
0.088, 0.128 |
2.0, 1.6, 1.5, 0.7, 1.8, 1.3, 1.0, 1.2, 1.2, 1.4 |
Y |
micro SMD-5 |
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800 |
6 |
1.575, 1.875, 1.275 |
0.075 |
1.8 |
Y |
TO-263-5, TO-220-5, PSOP-8 |
|
800 |
5.5 |
0.875, 1.575, 1.275, Adj |
0.075 |
1.5, 0.8, 1.2, Adj |
— |
TO-263-5, TO-220-5 |
|
800 |
5.5 |
1.6, 1.3, 1.9 |
0.1 |
1.5, 1.8, 1.2 |
Y |
TO-263-5, TO-220-5, PSOP-8 |
|
1500 |
6 |
1.61, 1.31, 1.91 |
0.11 |
1.8 |
Y |
TO-263-5, TO-220-5, PSOP-8 |
|
1500 |
5.5 |
0.915, 1.315, 1.615, Adj |
0.115 |
1.5, 0.8, 1.2, Adj |
— |
TO-263-5, TO-220-5 |
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3000 |
5.5 |
1.71, 2.01, 1.41 |
0.21 |
1.5, 1.8, 1.2 |
Y |
TO-263-5, TO-220-5 |
|
3000 |
5.5 |
1.01, 1.71, 1.41 |
0.21 |
1.5, 0.8, 1.2 |
— |
TO-263-5, TO-220-5 |
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3000 |
7 |
2.5 |
0.39 |
5| 1.8| 2.5| 3.3 |
Y |
TO-263-5, TO-220-5 |
Wide Input Voltage LDOs
National's wide VIN LDOs can be powered from 12V and higher input rails which make them useful in a wide variety of applications. A sampling of the broad portfolio is listed below, ordered by output current. See the full parametric catalog for more selections.
| Product ID |
Load (mA) |
Vin Max (V) |
VIN Min (V) |
Dropout Voltage) |
Enable Pin |
VOUT |
Package |
|
50 |
16 |
2.1 |
0.12 |
Y |
4.7, 3, 3.6, 2.5, 3.2, 2.9, 2.6, 3.3, 3.5, 3.8, 5, 2.7, 3.1, 4.5, 4, 2.8 |
SOT-23-5 |
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50 |
16 |
5.42, 2.72, 4.62, 2.92, 5.12, 4.82, 2.62, 3.42, 3.12, 4.12, 3.92, 3.72 |
0.12 |
Y |
4.7, 3.8, 3, 5, 3.6, 5.3, 2.5, 4.5, 4, 2.8, 2.6, 3.3 |
SOT-23-5 |
|
50 |
60, 40 |
3.3 |
0.4 |
Y |
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50 |
40 |
3.7 |
0.4 |
Y |
|
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100 |
26 |
|
0.6 |
Y |
|
|
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100 |
16 |
3, 3.2, 2.9, 3.3, 3.5, 3.8, 4.9, 2.7, 3.4, 3.1, 4, 4.2, 5.2 |
0.2 |
Y |
4.7, 3, 3.6, 2.5, 3.2, 2.9, 3.3, 3.8, 2.7, 5, 3.1, 4, 2.8 |
SOT-23-5 |
|
150 |
26 |
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0.6 |
— |
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|
|
150 |
26 |
|
0.6 |
— |
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|
|
150 |
52 |
|
0.4 |
Y |
|
|
|
150 |
16 |
2.2 |
1.3, 1, 1.2 |
Y |
0.9, 1.2, 1, 3.3 |
SOT-23-5 |
|
150 |
16 |
2.2 |
0.28 |
Y |
3.0, 2.85, 3.3 |
SOT-23-5, uSMD-5 |
|
150 |
16 |
2.5 |
0.28 |
Y |
3, 3.6, 2.5, 3.2, 6.1, 2.9, 2.6, 3.3, 3.8, 3.5, 2.4, 5, 2.7, 3.1, 4.5, 4, 2.8 |
SOT-23-5, uSMD-5 |
|
200 |
16 |
2.1 |
0.18 |
Y |
3, 5, 3.3 |
MSOP-8, LLP-8, SOIC NARROW-8 |
|
200 |
16 |
3.98, 3.38, 2.1, 2.98 |
0.18 |
Y |
3.8, 3, 5, 3.2, 2.8, 3.3 |
MSOP-8, LLP-8, SOIC NARROW-8 |
|
200 |
16 |
3.98, 2.1, 2.98 |
0.18 |
Y |
5.7, 3.8, 3, 2.7, 5, 3.2, 2.8, 3.3 |
MSOP-8, LLP-8, SOIC NARROW-8 |
|
250 |
26 |
5.3 |
0.8 |
Y |
|
|
|
250 |
26 |
5.3 |
0.8 |
Y |
|
|
|
250 |
30 |
|
0.6 |
Y |
|
|
|
250 |
30 |
|
0.6 |
Y |
|
|
|
250 |
30 |
|
0.6 |
Y |
|
|
|
250 |
30 |
|
0.6 |
Y |
|
|
|
250 |
16 |
2.5 |
0.45 |
Y |
1.5, 5, 1.8, 2.5, 3.3 |
SOT-23-5, LLP-6 |
|
500 |
16 |
5.31, 3.11, 2.81, 3.61 |
0.31 |
Y |
3, 5, 3.6, 2.5, 4, 2.85, 2.8, 3.3 |
MSOP-8, LLP-8, SOIC NARROW-8 |
|
500 |
16 |
2.1 |
0.31 |
Y |
1.8 |
MSOP-8, LLP-8, SOIC NARROW-8 |
|
500 |
10 |
2.7 |
0.25 |
— |
1.8, 2.5, 3.3, 5 |
SOT223-5, LLP-6 |
|
500 |
10 |
2.7 |
0.25 |
Y |
1.8, 2.5, 3.3, 5 |
SOT223-5, LLP-6 |
|
800 |
16 |
2.5 |
0.475 |
Y |
adj |
LLP-8, PSOP-8 |
|
1000 |
26 |
|
0.7 |
— |
|
|
|
1000 |
26 |
|
0.8 |
Y |
|
|
|
1000 |
0.3 |
-26 |
0.6 |
Y |
— |
TO-263-3, TO-220-3 |
|
1000 |
10 |
2.7 |
0.45 |
— |
1.8, 2.5, 3.3, 5 |
SOT223-5, LLP-6 |
|
1000 |
10 |
2.7 |
0.45 |
Y |
1.8, 2.5, 3.3, 5 |
SOT223-5, LLP-6 |
|
1500 |
0.3 |
-26 |
0.6 |
— |
-5.2, -5, -12, -15 |
TO-263-3, TO-220-3 |
|
Note1 |
24 |
1.8 |
— |
Y |
12, 3.3, 5 |
MSOP-8 |
Low IQ LDOs
These LDOs have low quiescent current consumption to maximize run time in battery powered applications. Quiescent current is used to describe a load that is powered up and consuming <1mA rather than its full load current. This type of keep alive circuit is useful for systems that spend most of their time in a sleep state waiting for an event to occur.
| Product ID |
Output Current (mA) |
Input Max Voltage (V) |
Input Min Voltage (V) |
Dropout Voltage (V) |
Quiescent Current (mA) |
On/Off Pin |
Output Voltage (V) |
Package |
|
50 |
60 |
4, 5.5V |
0.2 |
0.015 |
Y |
3, 3.3, 5 |
SOT-223, SOIC, TO-252, TO-92 |
|
500 |
10 |
2.7 |
0.25 |
0.055 |
N |
1.8, 2.5, 3.3, 5, Adj |
LLP |
|
500 |
10 |
2.7 |
0.25 |
0.055 |
Y |
1.8, 2.5, 3.3, 5, Adj |
LLP, SOT-223 |
|
1000 |
10 |
2.7 |
0.45 |
0.055 |
Y |
1.8, 2.5, 3.3, 5, Adj |
LLP, SOT-223 |
|
1000 |
10 |
2.7 |
0.42 |
0.019 |
N |
Adj |
LLP, TO-252 |
|
150 |
6 |
3.8, 3, 2, 2.3, 3.3 |
0.06 |
0.043 |
Y |
1.5, 3.8, 1.8, 2.5, 0.8, 1.35, 2.8, 1.2, 3.3 |
micro SMD-4, SOT23-5, LLP-6 |
|
150 |
6 |
2.5 |
0.06 |
0.08 |
Y |
1.5, 1.8, 3.1, 2 |
micro SMD-4, SOT23-5 |
|
150 |
6 |
2.5 |
0.06 |
0.085 |
Y |
4.7, 3, 5, 2.7, 3.2, 2.5, 3.1, 2.9, 2.8, 2.6, 3.3 |
micro SMD-5, SOT23-5 |
|
150 |
6 |
2.7, 3.2, 3.1, 2.8 |
0.08 |
0.085 |
Y |
3, 2.5, 2.85, 2.6 |
micro SMD-5, SOT23-5 |
|
300 |
3.6 |
1.65 |
0.075, Undefined |
0.05 |
Y |
1.5, 1.3, 2.8, 1.2 |
micro SMD-4 |
|
300 |
6 |
2.5 |
0.12 |
0.09 |
Y |
2.77, 3, 1.8, 2.5, 2.82, 3.3 |
LLP-8, MSOP-8 |
AECQ-Qualified LDOs
LDOs with AECQ-100 certification are especially important to automotive OEMs with their stringent quality requirements. With AECQ-100 certification, customers are assured of getting the most reliable LDOs available.
| Product ID |
IOUT (mA) |
VIN Max |
VIN Min |
Dropout (V) |
VOUT |
On/Off |
Package |
|
50 |
60 |
4, 5.5V |
0.2 |
3, 3.3, 5 |
Y |
SOT-223, SOIC, TO-252, TO-92 |
|
50 |
40 |
-45 |
0.400 |
3.3, 5 |
N |
PSOP, TO-252 |
|
150 |
40 |
3.65, 5.4 |
0.25 |
3.3, 5 |
Y |
PSOP, TO-263 |
|
500 |
10 |
2.7 |
0.25 |
1.8, 2.5, 3.3, 5, Adj |
N |
LLP |
FlexCap LDO Family
A proprietary compensation algorithm allows these LDOs to be stable regardless of the output capacitor ESR. LP3850x LDOs introduced National's TO-263 Thin package which is footprint compatible with the TO-263 but half the height with its high thermal dissipation characteristics. For more information, refer to App Notes: AN-1824 FlexCap Technology Simplifies LDO Design and AN-1797 TO-263 THIN Package.
| Product ID |
Load Current (A) |
VIN Min (V) |
VIN Max (V) |
VOUT (V) |
Typical Dropout (mV) |
Enable |
Packaging |
|
3 |
2.7 |
5.5 |
ADJ down to 0.6 |
450m |
— |
TO263-5 |
|
1.5 |
2.7 |
5.5 |
ADJ down to 0.6 |
220m |
Y |
TO263-, LLP-8 |
|
3 |
2.7 |
5.5 |
ADJ down to 0.6 |
450m |
Y |
TO263-5 |
|
1.5 |
2.7 |
5.5 |
ADJ down to 0.6 |
220m |
— |
TO263-5, LLP-8 |
Multi-Output LDOs
These LDOs have multiple outputs which save PCB area compared to multiple, individual devices.
| Product ID |
Input Max Voltage (V) |
Input Min Voltage (V) |
Output1 VOUTMin |
Output2 VOUTMin |
Output1 IOUTMax |
Output2 IOUTMax |
Dropout Voltage (V) |
Quiescent Current (mA) |
Error Flag |
Power on Reset |
|
7 |
2.7 |
1.8 |
1.8 |
150 |
150 |
0.135 |
0.34 |
Y |
— |
|
16 |
2.1 |
1.8 |
2.5 |
150 |
150 |
0.275 |
0.34 |
— |
Y |
|
6 |
2.5 |
2.5 |
2.8 |
300 |
150 |
0.06 |
0.075 |
— |
— |
|
6 |
2 |
0.8 |
0.8 |
150 |
300 |
0.21 |
0.07 |
Y |
Y |
|
6 |
2 |
0.8 |
0.8 |
150 |
300 |
0.21 |
0.07 |
— |
— |
|
5.5 |
1.8 |
2.7 |
1.8 |
280 |
280 |
0.11 |
90 |
— |
— |
Negative LDOs
These LDOs accept a negative input voltage and are typically used to power signal chain circuits, such as amplifiers or ADCs.
| Product ID |
Output Current (mA) |
Input Max Voltage (V) |
Input Min Voltage (V) |
Dropout Voltage (V) |
Output Voltage (V) |
On/Off Pin |
Package |
|
1000 |
-26 |
|
1 |
-5, -5.2, -12 |
— |
TO220, TO263 |
|
1000 |
-26 |
|
1 |
ADJ, -2 to
-25V |
Y |
TO220, TO263 |
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