LT3092EST#TRPBF Linear Technology, LT3092EST#TRPBF Datasheet - Page 14

• Manufacturer Part Number: LT3092EST#TRPBF
• Description: IC PROG CURRENT SOURCE SOT223-3
• Manufacturer: Linear Technology

Specifications of LT3092EST#TRPBF

• Function: Current Source
• Accuracy: ±1%
• Voltage - Input: 1.2 ~ 40 V
• Current - Output: 200mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-223 (3 leads + Tab), SC-73, TO-261
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Sensing Method: -

LT3092
APPLICATIONS INFORMATION
Demo circuit 1531A’s board layout using multiple inner
V
performance for the DFN package.
Table 2. DD Package, 8-Lead DFN
*Device is mounted on topside
Table 3. TS8 Package, 8-Lead SOT-23
Table 4. ST Package, 3-Lead SOT-223
*Device is mounted on topside
For further information on thermal resistance and using thermal information,
refer to JEDEC standard JESD51, notably JESD51-12.
Calculating Junction Temperature
Example: Given an industrial factory application with an
input voltage of 15V ±10%, an output voltage of 12V ±5%,
an output current of 200mA and a maximum ambient
temperature of 50°C, what would be the maximum junc-
tion temperature for a DFN package?
The total circuit power equals:
The SET pin current is negligible and can be ignored.
14
*Device is mounted on topside
TOPSIDE*
TOPSIDE*
TOPSIDE*
OUT
2500mm
1000mm
2500mm
1000mm
2500mm
1000mm
225mm
100mm
225mm
100mm
225mm
100mm
P
TOTAL
COPPER AREA
COPPER AREA
COPPER AREA
planes and multiple thermal vias achieves 28°C/W
2
2
2
2
2
2
2
2
2
2
2
2
= (V
BACKSIDE
BACKSIDE
BACKSIDE
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
IN
– V
2
2
2
2
2
2
2
2
2
2
2
2
OUT
BOARD AREA
BOARD AREA
BOARD AREA
)(I
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
OUT
)
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
25°C/W
25°C/W
28°C/W
32°C/W
54°C/W
54°C/W
57°C/W
63°C/W
20°C/W
20°C/W
24°C/W
29°C/W
V
V
I
Power dissipation under these conditions equals:
Junction temperature equals:
In this example, the junction temperature is below the
maximum rating, ensuring reliable operation.
Protection Features
The LT3092 incorporates several protection features ideal
for battery-powered circuits, among other applications.
In addition to normal circuit protection features such as
current limiting and thermal limiting, the LT3092 protects
itself against reverse-input voltages, reverse-output volt-
ages, and reverse OUT-to-SET pin voltages.
Current limit protection and thermal overload protection
protect the IC against output current overload condi-
tions. For normal operation, do not exceed a junction
temperature of 125°C. The thermal shutdown circuit’s
typical temperature threshold is 165°C and has about
5°C of hysteresis.
The LT3092’s IN pin withstands ±40V voltages with respect
to the SET and OUT pins. Reverse-current fl ow, if OUT is
greater than IN, is less than 1mA (typically under 100μA),
protecting the LT3092 and sensitive loads.
Clamping diodes and 1k limiting resistors protect the
LT3092’s SET pin relative to the OUT pin voltage. These
protection components typically only carry current under
transient overload conditions. These devices are sized to
handle ±10V differential voltages and ±15mA crosspin
current fl ow without concern.
OUT
IN(MAX CONTINUOUS)
OUT(MIN CONTINUOUS)
P
T
T
TOTAL
J
J
= 200mA
= T
= 50°C + (1.02W • 30°C/W) = 80.6°C
A
= (16.5 – 11.4V)(200mA) = 1.02W
+ P
TOTAL
• θ
= 16.5 (15V + 10%)
= 11.4V (12V – 5%)
JA
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