LT1129IST-3-3 Datasheet, PDF (1/16 Pages) Linear Technology – Micropower Low Dropout Regulators with Shutdown

FEATURES
n _{400mV Dropout Voltage}
n _{700mA Output Current}
n _{50μA Quiescent Current}
n _{No Protection Diodes Needed}
n _{Adjustable Output from 3.8V to 30V}
n _{3.3V and 5V Fixed Output Voltages}
n _{Controlled Quiescent Current in Dropout}
n _Shutdown
n _{16μA Quiescent Current in Shutdown}
n _{Stable with 3.3μF Output Capacitor}
n _{Reverse Battery Protection}
n _{No Reverse Output Current}
n _{Thermal Limiting}
n _{Surface Mount SOT-223 and DD-Pak Packages}
APPLICATIONS
n _{Low Current Regulator}
n _{Regulator for Battery-Powered Systems}
n _{Post Regulator for Switching Supplies}
n _{5V to 3.3V Logic Regulator}
LT1129/LT1129-3.3/LT1129-5
Micropower Low Dropout
Regulators with Shutdown
DESCRIPTION
The LT^®1129/LT1129-3.3/LT1129-5 are micropower low
dropout regulators with shutdown. The devices are capable
of supplying 700mA of output current with a dropout
voltage of 400mV at maximum output. Designed for use
in battery-powered systems, the low quiescent current,
50μA operating and 16μA in shutdown, make them an ideal
choice. The quiescent current does not rise in dropout as
it does with many other low dropout PNP regulators.
Other features of the LT1129 /LT1129-3.3/LT1129-5 include
the ability to operate with small output capacitors. They
are stable with only 3.3μF on the output while most older
devices require between 10μF and 100μF for stability. Also
the input may be connected to ground or a reverse voltage
without reverse current flow from output to input. This
makes the LT1129/LT1129-3.3/LT1129-5 ideal for backup
power situations where the output is held high and the
input is at ground or reversed. Under these conditions,
only 16μA will flow from the output pin to ground. The
devices are available in 5-lead TO-220, 5-lead DD-Pak and
3-lead SOT-223 packages.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
V_IN > 5.5V
5V Supply with Shutdown
5
IN
1
OUT
LT1129-5
4 _SHDN
2
SENSE
GND
3
5V OUT
500mA
+
3.3μF
SOLID TANTALUM
V_SHDN (PIN 4) OUTPUT
< 0.25
OFF
> 2.8
ON
NC
ON
112935 TA01
Dropout Voltage
0.6
0.5
0.4
0.3
0.2
0.1
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
OUTPUT CURRENT (A)
112935 TA02
112935ff
1