LP38691-ADJ/LP38693-ADJ 500mA Low Dropout CMOS Linear Regulators with Adjustable Output
Stable with Ceramic Output Capacitors
PRELIMINARY
January 2005
LP38691-ADJ/LP38693-ADJ
500mA Low Dropout CMOS Linear Regulators with
Adjustable Output
Stable with Ceramic Output Capacitors
General Description
The LP38691/3-ADJ low dropout CMOS linear regulators
provide 2.0% precision reference voltage, extremely low
dropout voltage (250mV
@
500mA load current, V
OUT
= 5V)
and excellent AC performance utilizing ultra low ESR ce-
ramic output capacitors.
The low thermal resistance of the LLP and SOT-223 pack-
ages allow the full operating current to be used even in high
ambient temperature environments.
The use of a PMOS power transistor means that no DC base
drive current is required to bias it allowing ground pin current
to remain below 100 µA regardless of load current, input
voltage, or operating temperature.
Dropout Voltage:
250 mV (typ)
@
500mA (typ. 5V out).
Ground Pin Current:
55 µA (typ) at full load.
Adjust Pin Voltage:
2.0% (25˚C) accuracy.
Features
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Output voltage range of 1.25V - 9V
2.0% adjust pin voltage accuracy (25˚C)
Low dropout voltage: 250mV
@
500mA (typ, 5V out)
Wide input voltage range (2.7V to 10V)
Precision (trimmed) bandgap reference
Guaranteed specs for -40˚C to +125˚C
1µA off-state quiescent current
Thermal overload protection
Foldback current limiting
SOT-223 and 6-Lead LLP packages
Enable pin (LP38693-ADJ)
Applications
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Hard Disk Drives
Notebook Computers
Battery Powered Devices
Portable Instrumentation
Typical Application Circuits
20126801
20126802
V
OUT
= V
ADJ
x (1 + R1/R2)
Note:
*Minimum value required for stability.
© 2005 National Semiconductor Corporation
DS201268
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
