LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
1
1117fd
TYPICAL APPLICATION
FEATURES DESCRIPTION
800mA Low Dropout
Positive Regulators Adjustable
and Fixed 2.85V, 3.3V, 5V
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 profi le 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 fl ows into the load, increasing effi ciency.
Dropout Voltage (V
IN
– V
OUT
)
APPLICATIONS
n
Space Saving SOT-223 Surface Mount Package
n
3-Terminal Adjustable or Fixed 2.85V, 3.3V, 5V
n
Output Current of 800mA
n
Operates Down to 1V Dropout
n
Guaranteed Dropout Voltage at Multiple Current Levels
n
0.2% Line Regulation Max
n
0.4% Load Regulation Max
n
Active SCSI Terminators
n
High Effi ciency Linear Regulators
n
Post Regulators for Switching Supplies
n
Battery Chargers
n
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.
OUTPUT CURRENT (mA)
0
0
DROPOUT VOLTAGE (V)
0.2
0.4
0.6
0.8
1.0
1.4
100 400 600 800
1117 TA02
1.2
200 300 500 700
T
J
= 25°C
T
J
= 125°C
INDICATES GUARANTEED TEST POINT
0°C ≤ T
J
≤ 125°C
–40°C ≤ T
J
< 0°C
18 TO 27
LINES
1117 TA01
10µF
110
110
110
110
4.75V TO
5.25V
22µF
LT1117-2.85
IN
GND
OUT
+ +
Active Terminator for SCSI-2 Bus
