September 1997
LP2975
MOSFET LDO Driver/Controller
General Description
Features
n Simple to use, few external components
n Ultra-small mini SO-8 package
A high-current LDO regulator is simple to design with the
LP2975 LDO Controller. Using an external P-FET, the
LP2975 will deliver an ultra low dropout regulator with ex-
tremely low quiescent current.
n 1.5% (A grade) precision output voltage
n Low-power shutdown input
High open loop gain assures excellent regulation and ripple
rejection performance.
<
n
1 µA in shutdown
@
n Low operating current (180 µA typical VIN = 5V)
n Wide supply voltage range (1.8V to 24V)
n Built-in current limit amplifier
The trimmed internal bandgap reference provides precise
output voltage over the entire operating temperature range.
Dropout voltage is “user selectable” by sizing the external
FET: the minimum input-output voltage required for opera-
tion is the maximum load current multiplied by the RDS(ON)
of the FET.
n Overtemperature protection
n 12V, 5V, and 3.3V standard output voltages
n Can be programmed using external divider
n −40˚C to +125˚C junction temperature range
Overcurrent protection of the external FET is easily imple-
mented by placing a sense resistor in series with VIN. The
57 mV detection threshold of the current sense circuitry mini-
mizes dropout voltage and power dissipation in the resistor.
Applications
n High-current 5V to 3.3V regulator
n Post regulator for switching converter
n Current-limited switch
The standard product versions available provide output volt-
ages of 12V, 5V, or 3.3V with guaranteed 25˚C accuracy of
1.5% (“A” grade) and 2.5% (standard grade).
Block Diagram
Connection Diagram
Surface Mount Mini SO-8 Package
DS100034-2
Top View
For Order Numbers
See Table 1 of this Document
See NS Package Number MUA08A
DS100034-1
*R
values are: 208k for 12V part, 72.8k for 5V part, and 39.9k for 3.3V
SET
part.
© 1999 National Semiconductor Corporation
DS100034
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