LP2950 Datasheet, PDF (1/13 Pages) National Semiconductor (TI) – Series of Adjustable Micropower Voltage Regulators

LP2950/LP2951
100mA Low Dropout Voltage Regulators
FEATURES
• 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
LP2951 versions only
• Error Flag Warns of Output Dropout
• Logic-Controlled Electronic Shutdown
• Output Programmable From 1.24 to 29V
APPLICATIONS
• 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
Now Available in Lead Free Packaging
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
FROM
CMOS OR
TTL
3
SHUTDOWN
+
_
ERROR
AMPLIFIER
180kΩ
60 mV
+
+
60kΩ
_
ERROR DETECTION
+ 1.23V
COMPARATOR
REFERENCE
2
SENSE
6
5V TAP
5
______
ERROR
4
GROUND
5V @ 100mA
MAX
330kΩ
+
1µF
.
.
TO CMOS OR
TTL
Rev. 8/10/01
LP2950/51 100mA Low Dropout Voltage Regulators
1
©Copyright 2001 Sipex Corporation