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.
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
CC
Block Diagram
LP2956
DS011339-1
May 1999
LP2956/LP2956A
Dual
Micropower
Low-Dropout
V
oltage
Regulators
© 1999 National Semiconductor Corporation DS011339 www.national.com