LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
800mA Low Dropout
Positive Regulators Adjustable
and Fixed 2.85V, 3.3V, 5V
FEATURES
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DESCRIPTION
The LT
®
1117 is a positive low dropout regulator designed
to provide up to 800mA of output current. The device is
available in an adjustable version and fixed output voltages
of 2.85V, 3.3V and 5V. The 2.85V version is designed
specifically to be used in Active Terminators for the SCSI
bus. All internal circuitry is designed to operate down to 1V
input to output differential. Dropout voltage is guaranteed
at a maximum of 1.2V at 800mA, decreasing at lower load
currents. On chip trimming adjusts the reference/output
voltage to within ± 1%. Current limit is also trimmed in
order to minimize the stress on both the regulator and the
power source circuitry under overload conditions.
The low profile surface mount SOT-223 package allows the
device to be used in applications where space is limited. The
LT1117 requires a minimum of 10μF of output capacitance
for stability. Output capacitors of this size or larger are
normally included in most regulator designs.
Unlike PNP type regulators where up to 10% of the output
current is wasted as quiescent current, the quiescent current
of the LT1117 flows into the load, increasing efficiency.
Space Saving SOT-223 Surface Mount Package
3-Terminal Adjustable or Fixed 2.85V, 3.3V, 5V
Output Current of 800mA
Operates Down to 1V Dropout
Guaranteed Dropout Voltage at Multiple Current Levels
0.2% Line Regulation Max
0.4% Load Regulation Max
APPLICATIONS
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Active SCSI Terminators
High Efficiency Linear Regulators
Post Regulators for Switching Supplies
Battery Chargers
5V to 3.3V Linear Regulators
L,
LT, LTC, LTM, Linear Technology, OPTI-LOOP and the Linear logo are registered trademarks
of Linear Technology Corporation. UltraFast is a trademark of Linear Technology Corporation. All
other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Active Terminator for SCSI-2 Bus
1.4
110Ω
110Ω
LT1117-2.85
IN
4.75V TO
5.25V
OUT
GND
10μF
DROPOUT VOLTAGE (V)
110Ω
18 TO 27
LINES
1.2
1.0
T
J
= 25°C
0.8
0.6
0.4
0.2
INDICATES GUARANTEED TEST POINT
0
0
100 200 300 400 500 600 700 800
OUTPUT CURRENT (mA)
1117 TA02
Dropout Voltage (V
IN
– V
OUT
)
–40°C ≤ T
J
< 0°C
0°C ≤ T
J
≤ 125°C
+
+
22μF
T
J
= 125°C
110Ω
1117 TA01
1117fd
1
LINER [ LINEAR TECHNOLOGY ]
