LT1118 Datasheet, PDF (6/8 Pages) Linear Technology – Low IQ, Low Dropout, 800mA, Source and Sink Regulators Adjustable and Fixed 2.5V, 2.85V, 5V Output

LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
U
OPERATIO
thermally connected to the die substrate. Table 1 shows
measured thermal resistance from junction to ambient for
the LT1118 connected to various sized PC board ground
planes. The power dissipated in the LT1118 varies with
input voltage and loading. When the regulator is sourcing
current the power which must be dissipated by the pack-
age is:
P_D = (V_IN – V_OUT) • I_LOAD.
When the regulator is sinking load current, power dissipa-
tion is nearly independent of V_IN and can be calculated as:
P_D = V_OUT • I_LOAD.
Heat sinking to the IC package must consider the worst
case power dissipation which may occur.
Table 1. Measured Thermal Resistance from Junction to
Ambient for the LT1118
S8 Package
SOT-223
Free Air
1 Sq Inch Copper
120°C/W
55°C/W
95°C/W
53°C/W
4 Sq Inch Copper
35°C/W
38°C/W
TYPICAL APPLICATIONS
SCSI Active Terminator
TERMPWR
110Ω
•••• _110Ω
110Ω
IN LT1118-2.85 OUT
+
GND
5V
2.2µF
110Ω
•••• _110Ω
1µF
27 LINES
1118 TA03
6
Power Supply Splitter
V_IN
5V
5V
1µF
IN LT1118-2.5 OUT
GND
ANALOG
COMMON
2.5V
1µF
1118 TA04