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
Features
n Output voltage range of 1.25V - 9V
n 2.0% adjust pin voltage accuracy (25˚C)
@
dropout voltage (250mV 500mA load current, VOUT = 5V)
@
n Low dropout voltage: 250mV 500mA (typ, 5V out)
and excellent AC performance utilizing ultra low ESR ce-
ramic output capacitors.
n Wide input voltage range (2.7V to 10V)
n Precision (trimmed) bandgap reference
n Guaranteed specs for -40˚C to +125˚C
n 1µA off-state quiescent current
n Thermal overload protection
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.
n Foldback current limiting
n SOT-223 and 6-Lead LLP packages
n Enable pin (LP38693-ADJ)
@
Dropout Voltage: 250 mV (typ) 500mA (typ. 5V out).
Applications
Ground Pin Current: 55 µA (typ) at full load.
Adjust Pin Voltage: 2.0% (25˚C) accuracy.
n Hard Disk Drives
n Notebook Computers
n Battery Powered Devices
n Portable Instrumentation
Typical Application Circuits
20126801
20126802
VOUT = VADJ x (1 + R1/R2)
Note: *Minimum value required for stability.
© 2005 National Semiconductor Corporation
DS201268
www.national.com
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