LT1117 Datasheet, PDF (1/12 Pages) Linear Technology – 800mA Low Dropout Positive Regulators Adjustable and Fixed 2.85V, 3.3V, 5V

LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
800mA Low Dropout
Positive Regulators
Adjustable and Fixed 2.85V,
3.3V, 5V
FEATURES
s _{Space Saving SOT-223 Surface Mount Package}
s _{Three-Terminal Adjustable or Fixed 2.85V, 3.3V, 5V}
s _{Output Current of 800mA}
s _{Operates Down to 1V Dropout}
s _{Guaranteed Dropout Voltage at Multiple Current Levels}
s _{0.2% Line Regulation Max}
s _{0.4% Load Regulation Max}
APPLICATI S
s _{Active SCSI Terminators}
s _{High Efficiency Linear Regulators}
s _{Post Regulators for Switching Supplies}
s _{Battery Chargers}
s _{5V to 3.3V Linear Regulators}
DESCRIPTIO
The LT1117 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.
TYPICAL APPLICATI
Active Terminator for SCSI-2 Bus
4.75V TO
5.25V
LT1117-2.85
IN
OUT
+
GND
10µF
+
22µF
110Ω
110Ω
110Ω
110Ω
18 TO 27
LINES
LT1117 • TA01
Dropout Voltage (V_IN – V_OUT)
1.4
1.2
T_J = 25°C
1.0
0.8
T_J = 125°C
0.6
0.4
0.2
0
0
INDICATES GUARANTEED TEST POINT
100 200 300 400 500 600 700 800
OUTPUT CURRENT (mA)
LT1117 • TPC01
1