LT1965IQ#TRPBF Linear Technology, LT1965IQ#TRPBF Datasheet - Page 15
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LT1965IQ#TRPBF
Manufacturer Part Number
LT1965IQ#TRPBF
Description
IC REG LDO 1.1A 5-DD
Manufacturer
Linear Technology
Datasheet
1.LT1965EDD-3.3PBF.pdf
(20 pages)
Specifications of LT1965IQ#TRPBF
Regulator Topology
Positive Adjustable
Voltage - Output
1.2 ~ 19.5 V
Voltage - Input
1.8 ~ 20 V
Voltage - Dropout (typical)
0.31V @ 1.1A
Number Of Regulators
1
Current - Output
1.1A
Current - Limit (min)
1.2A
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
TO-263-5, D²Pak (5 leads + Tab), TO-263BA
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
APPLICATIONS INFORMATION
The following tables list thermal resistance for several
different board sizes and copper areas. All measurements
were taken in still air on 1/16" FR-4 board with one ounce
copper.
Table 1. Measured Thermal Resistance for DFN Package
*Device is mounted on topside
Table 2. Measured Thermal Resistance for MSOP Package
*Device is mounted on topside
Table 3. Measured Thermal Resistance for DD-PAK Package
*Device is mounted on topside
Measured Thermal Resistance for TO-220 Package
Thermal Resistance (Junction-to-Case) = 3°C/W
2500mm
1000mm
2500mm
1000mm
2500mm
1000mm
Topside*
Topside*
Topside*
225mm
100mm
225mm
100mm
125mm
50mm
50mm
Copper Area
Copper Area
Copper Area
2
2
2
2
2
2
2
2
2
2
2
2
2
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
Backside
Backside
Backside
2
2
2
2
2
2
2
2
2
2
2
2
2
Board Area
Board Area
Board Area
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2
2
2
2
2
2
2
2
2
2
2
2
2
(Junction-to-Ambient)
(Junction-to-Ambient)
(Junction-to-Ambient)
Thermal Resistance
Thermal Resistance
Thermal Resistance
60°C/W
62°C/W
65°C/W
68°C/W
70°C/W
55°C/W
57°C/W
60°C/W
65°C/W
68°C/W
25°C/W
30°C/W
35°C/W
Calculating Junction Temperature
Example: Given an output voltage of 2.5V, an input voltage
range of 3.3V ± 5%, an output current range of 0mA to
500mA and a maximum ambient temperature of 85°C,
what will the maximum junction temperature be?
The power dissipated by the device equals:
where:
So,
Using a DFN package, the thermal resistance will be in
the range of 60°C/W to 70°C/W depending on the cop-
per area. So the junction temperature rise above ambient
approximately equals:
The maximum junction temperature equals the maximum
ambient temperature plus the maximum junction tempera-
ture rise above ambient or:
I
I
V
I
P = 500mA(3.465V – 2.5V) + 8.2mA(3.465V) = 0.511W
0.511W • 65°C/W = 33.22°C
T
OUT(MAX)
OUT(MAX)
GND
JMAX
IN(MAX)
at (I
= 85°C + 33.22°C = 118.22°C
= 3.465V
OUT
• (V
= 500mA
= 500mA, V
IN(MAX)
– V
OUT
IN
LT1965 Series
= 3.465V) = 8.2mA
) + I
GND
• V
IN(MAX)
15
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