LT1529
LT1529-3.3/LT1529-5
3A Low Dropout Regulators
with Micropower
Quiescent Current
and Shutdown
DESCRIPTIO
The LT
®
1529/LT1529-3.3/LT1529-5 are 3A low dropout
regulators with micropower quiescent current and shut-
down. The devices are capable of supplying 3A of output
current with a dropout voltage of 0.6V. 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 is well controlled; it
does not rise in dropout as it does with many other low
dropout PNP regulators.
Other features of the LT1529 /LT1529-3.3/LT1529-5 in-
clude 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 stabil-
ity. Small ceramic capacitors can be used, enhancing
manufacturabiltiy. Also the input may be connected to
voltages lower than the output voltage, including negative
voltages, without reverse current flow from output to
input. This makes the LT1529/LT1529-3.3/LT1529-5 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 and
5-lead DD packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
FEATURES
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Dropout Voltage: 0.6V at I
OUT
= 3A
Output Current: 3A
Quiescent Current: 50µA
No Protection Diodes Needed
Adjustable Output from 3.8V to 14V
3.3V and 5V Fixed Output Voltages
Controlled Quiescent Current in Dropout
Shutdown I
Q
= 16µA
Stable with 3.3µF Output Capacitor
Reverse Battery Protection
No Reverse Current
Thermal Limiting
APPLICATIO S
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High Efficiency Regulator
Regulator for Battery-Powered Systems
Post Regulator for Switching Supplies
5V to 3.3V Logic Regulator
TYPICAL APPLICATIO
5
V
IN
> 5.5V
0.6
5V Supply with Shutdown
V
IN
OUTPUT
1
0.5
LT1529-5
4
SHDN SENSE
GND
3
2
+
3.3µF
SOLID
TANT
5V
3A
DROPOUT VOLTAGE (V)
0.4
0.3
0.2
0.1
V
SHDN
(PIN 4)
< 0.25
> 2.8
NC
OUTPUT
OFF
ON
ON
0
LT1529 • TA01
0
0.5
U
U
U
Dropout Voltage
1.0
1.5
2.0
OUTPUT CURRENT (A)
2.5
3.0
LT1529 • TA02
1
LINER [ LINEAR TECHNOLOGY ]
