LT3080EDD-1#PBF Linear Technology, LT3080EDD-1#PBF Datasheet - Page 15

• Manufacturer Part Number: LT3080EDD-1#PBF
• Description: IC REG LDO ADJ 1.1A 8-DFN
• Manufacturer: Linear Technology

Specifications of LT3080EDD-1#PBF

• Regulator Topology: Positive Adjustable
• Voltage - Output: 0 ~ 36 V
• Voltage - Input: 1.2 ~ 36 V
• Voltage - Dropout (typical): 1.35V @ 1.1A
• Number Of Regulators: 1
• Current - Output: 1.1A
• Current - Limit (min): 1.1A
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-DFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
Power dissipation under these conditions is equal to:
Junction Temperature will be equal to:
In this case, the junction temperature is below the maximum
rating, ensuring reliable operation.
Reducing Power Dissipation
In some applications it may be necessary to reduce
the power dissipation in the LT3080-1 package without
sacrifi cing output current capability. Two techniques
are available. The fi rst technique, illustrated in Figure 8,
employs a resistor in series with the regulator’s input. The
voltage drop across R
PDRIVE = (V
P
P
P
Total Power Dissipation = 721mW
T
T
I
CONTROL
J
J
DRIVE
OUTPUT
OUTPUT
= T
= 50°C + 721mW • 64°C/W = 96°C
A
= (3.630V – 0.9V)(17mA) = 46mW
+ P
= (V
= (1.575V – 0.9V)(1A) = 675mW
=
TOTAL
I
OUT
CONTROL
60
IN
– V
• θ
=
1
60
OUT
JA
S
A
decreases the LT3080-1’s IN-to-
– V
=
(approximated using tables)
)(I
17
OUT
OUT
mA
)(I
)
Figure 8. Reducing Power Dissipation Using a Series Resistor
CONTROL
C1
)
V
SET
R
CONTROL
SET
+
–
LT3080-1
OUT differential voltage and correspondingly decreases
the LT3080-1’s power dissipation.
As an example, assume: V
and I
Junction Temperature section previously discussed.
Without series resistor R
LT3080-1 equals:
If the voltage differential (V
transistor is chosen as 0.5V, then R
Power dissipation in the LT3080-1 now equals:
The LT3080-1’s power dissipation is now only 30%
compared to no series resistor. R
power. Choose appropriate wattage resistors to handle
and dissipate the power properly.
25mΩ
P
R
P
TOTAL
TOTAL
S
OUT(MAX)
OUT
=
IN
5
V
=
=
R
30801 F08
(
– .
(
S
C2
5
5
3 3
= 1A. Use the formulas from the Calculating
V
V
V
V
V
– .
1
IN
IN
OUT
– .
A
V
3 3
3 3
−
V
0 5
V
.
)
•
)
V
⎛
⎝ ⎜
•
IN
⎛
⎝ ⎜
1
60
=
S
A
= V
1
60
, power dissipation in the
1 2
DIFF
A
⎞
⎠ ⎟
. Ω
+
⎞
⎠ ⎟
CONTROL
(
) across the NPN pass
+
5
(
V
S
0 5
S
– .
.
dissipates 1.2W of
equals:
3 3
V
LT3080-1
= 5V, V
)
V
•
1
)
A
•
1
=
OUT
A
0 53
=
15
.
1
= 3.3V
.7 7 3W
30801fa
W