LP3962ES-3.3 National Semiconductor, LP3962ES-3.3 Datasheet - Page 16

• Manufacturer Part Number: LP3962ES-3.3
• Description: IC, LDO VOLT REG, 3.3V, 1.5A, TO-263-5
• Manufacturer: National Semiconductor

Specifications of LP3962ES-3.3

• Primary Input Voltage: 7V
• Output Voltage Fixed: 3.3V
• Dropout Voltage Vdo: 380mV
• No. Of Pins: 5
• Output Current: 1.5A
• Operating Temperature Range: -40°C To +125°C
• Termination Type: SMD
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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Applications Information
HEATSINKING TO-263 AND SOT-223 PACKAGES
The TO-263 and SOT223 packages use the copper plane on
the PCB as a heatsink. The tab of these packages are
soldered to the copper plane for heat sinking. Figure 3
shows a curve for the θ
copper area sizes, using a typical PCB with 1 ounce copper
and no solder mask over the copper area for heat sinking.
As shown in the figure, increasing the copper area beyond 1
square inch produces very little improvement. The minimum
value for θ
32˚C/W.
Figure 4 shows the maximum allowable power dissipation
for TO-263 packages for different ambient temperatures,
assuming θ
ture is 125˚C.
Figure 5 shows a curve for the θ
different copper area sizes, using a typical PCB with 1 ounce
copper and no solder mask over the copper area for heat
sinking.
FIGURE 3. θ
FIGURE 4. Maximum power dissipation vs ambient
JA
JA
temperature for TO-263 package
for the TO-263 packag mounted to a PCB is
is 35˚C/W and the maximum junction tempera-
JA
vs Copper(1 Ounce) Area for TO-263
JA
package
of TO-263 package for different
JA
of SOT-223 package for
(Continued)
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16
The following figures show different layout scenarios for
SOT-223 package.
FIGURE 5. θ
FIGURE 6. SCENARIO A, θ
FIGURE 7. SCENARIO B, θ
JA
vs Copper(1 Ounce) Area for SOT-223
package
JA
JA
= 148˚C/W
= 125˚C/W
10126619
10126621
10126620