Datasheet

LT1118/LT1118-2.5/
LT1118-2.85/LT1118-5
6
1118fd
OPERATION
SCSI Active Terminator
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 package 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
Power Supply Splitter
LT1118-2.85
GND
IN
27 LINES
2.2μF
5V
F
110Ω
110Ω
1118 TA03
110Ω
110Ω
110Ω
TERMPWR
OUT
+
LT1118-2.5
GND
IN
F
1118 TA04
5V
ANALOG
COMMON
2.5V
V
IN
5V
OUT
F