LP2956 National Semiconductor, LP2956 Datasheet

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LP2956

Manufacturer Part Number
LP2956
Description
Dual Micropower Low-Dropout Voltage Regulators
Manufacturer
National Semiconductor
Datasheet

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© 1999 National Semiconductor Corporation
LP2956/LP2956A
Dual Micropower Low-Dropout Voltage Regulators
General Description
The LP2956 is a micropower voltage regulator with very low
quiescent current (170 µA typical at light loads) and very low
dropout voltage (typically 60 mV at 1 mA load current and
470 mV at 250 mA load current on the main output).
The LP2956 retains all the desirable characteristics of the
LP2951, but offers increased output current (main output),
an auxiliary LDO adjustable regulated output (75 mA), and
additional features.
The auxiliary output is always on (regardless of main output
status), so it can be used to power memory circuits.
Quiescent current increases only slightly at dropout, which
prolongs battery life.
The error flag goes low if the main output voltage drops out
of regulation.
An open-collector auxiliary comparator is included, whose in-
verting input is tied to the 1.23V reference.
Reverse battery protection is provided.
The parts are available in DIP and surface mount packages.
Block Diagram
DS011339
LP2956
Features
n Output voltage adjusts from 1.23V to 29V
n Guaranteed 250 mA current (main output)
n Auxiliary LDO (75 mA) adjustable output
n Auxiliary comparator with open-collector output
n Shutdown pin for main output
n Extremely low quiescent current
n Low dropout voltage
n Extremely tight line and load regulation
n Very low temperature coefficient
n Current and thermal limiting
n Reverse battery protection
Applications
n High-efficiency linear regulator
n Low dropout battery-powered regulator
n µP system regulator with switchable high-current V
DS011339-1
www.national.com
May 1999
CC

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LP2956 Summary of contents

Page 1

... LP2956/LP2956A Dual Micropower Low-Dropout Voltage Regulators General Description The LP2956 is a micropower voltage regulator with very low quiescent current (170 µA typical at light loads) and very low dropout voltage (typically load current and 470 mV at 250 mA load current on the main output). ...

Page 2

... Connection Diagrams Order Number LP2956AMJ-QML or 5962-9554701QEA www.national.com 16–Pin DIP DS011339-2 Order Number LP2956IN or LP2956AIN See NS Package Number N16A See NS Package Number J16A 16-Pin Surface Mount DS011339-3 Order Number LP2956IM or LP2956AIM See NS Package Number M16A 2 ...

Page 3

... OUT 1.23 1.22 1.21 3 −20V to +30V −0.3V to +5V −0.3V to +5V −0.3V to +30V −0.3V to +30V −0.3V to +30V 2 kV LP2956AI LP2956I Units Max Min Max 5.025 4.950 5.050 5.060 4.900 5.100 V 5.070 4.880 5.120 100 150 ppm/˚C 0.1 0.2 % 0.2 ...

Page 4

... V 0. 150 IN (COMP) = 400 µ (Note 11) −240 (Note 11) −350 (Note 11) 110 (Note 12) 0. µA (SD IN) V 4.5V O (Note 14) 1.236 (Note 14) 1.230 4 LP2956AI LP2956I Units Min Max Min Max ppm/˚ 0.3 0.4 % 0.5 0.6 % 0.3 0.4 0.6 1.0 200 200 mV 300 300 600 600 mV 700 ...

Page 5

... Out (Main Out (Aux. Out 4.5V (Main Out) = 0.1 mA 270 (Aux. Out) = 0.1 mA 120 ) 1 µA (max), the junction-to-ambient thermal resistance OUT REF 5 LP2956AI LP2956I Units Min Max Min Max µ 250 250 mV 400 400 −30 30 −30 ...

Page 6

Electrical Characteristics Note 12: The shutdown input equivalent circuit is the base of a grounded-emitter NPN transistor in series with a current-limiting resistor. Pulling the shutdown input high turns off the main regulator. For more details, see Application Hints. Note ...

Page 7

Typical Performance Characteristics Output) and 10 µF (Auxiliary Output), Feedback is tied to 5V Tap pin, C Sense pin, Auxiliary Output is programmed for 5V. The main regulator output has load, the auxiliary output has a 100 ...

Page 8

Typical Performance Characteristics Output) and 10 µF (Auxiliary Output), Feedback is tied to 5V Tap pin, C Sense pin, Auxiliary Output is programmed for 5V. The main regulator output has load, the auxiliary output has a 100 ...

Page 9

Typical Performance Characteristics Output) and 10 µF (Auxiliary Output), Feedback is tied to 5V Tap pin, C Sense pin, Auxiliary Output is programmed for 5V. The main regulator output has load, the auxiliary output has a 100 ...

Page 10

... R The heatsink for the LP2956 is made using the PC board copper. The heat is conducted from the die, through the lead frame (inside the part), and out the pins which are soldered to the PC board. The pins used for heat conduction are shown in Table 1 ...

Page 11

Application Hints (Continued) ESR may increase by a factor the temperature is reduced from +25˚C to −30˚C). The value of these capaci- tors may be increased without limit. The main output requires less capacitance at ...

Page 12

... REF FB FIGURE 5. Auxiliary Adjustable Regulator AUXILIARY LDO OUTPUT The LP2956 has an auxiliary LDO regulator output (which can source mA) that is adjustable for voltages from 1.23V to 29V. The output voltage is set by an external resistive divider, as shown in Figure 5 . The maximum output current is 75 mA, and the output requires 10 µ ...

Page 13

Schematic Diagram 13 www.national.com ...

Page 14

Typical Applications www.national.com DS011339-16 14 ...

Page 15

... Physical Dimensions inches (millimeters) unless otherwise noted Order Number LP2956IM or LP2956AIM Order Number LP2956IN or LP2956AIN 16-Pin Surface Mount NS Package Number M16A 16-Pin Plastic Dual-In-Line Package NS Package Number N16A 15 www.national.com ...

Page 16

... Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Order Number LP2956AMJ-QML or 5962-9554701QEA 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 ...

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