Datasheet

LP38513-ADJ

SNVS514C –JANUARY 2009–REVISED APRIL 2013

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LP38513-ADJ is available in the TO-263 THIN surface mount package. For a comparison of the TO-263 THIN

package to the standard TO-263 package see Application Note AN-1797 TO-263 THIN Package SNVA328. The

thermal resistance depends on amount of copper area, or heat sink, and on air flow. See Application Note AN-

1520 A Guide to Board Layout for Best Thermal Resistance for Exposed Packages SNVA183 for guidelines.

Heat-Sinking the TO-263 THIN Package

The DAP of the TO-263 THIN package is soldered to the copper plane for heat sinking. The TO-263 THIN

package has a θ

rating of 67°C/W, and a θ

rating of 2°C/W. The θ

rating of 67°C/W includes the device

DAP soldered to an area of 0.055 square inches (0.22 in x 0.25 in) of 1 ounce copper on a two sided PCB, with

no airflow. See JEDEC standard EIA/JESD51-3 for more information.

Figure 19 shows a curve for the θ

of TO-263 THIN package for different thermal via counts under the exposed

DAP, using a four layer PCB for heat sinking. The thermal vias connect the copper area directly under the

exposed DAP to the first internal copper plane only. See JEDEC standards EIA/JESD51-5 and EIA/JESD51-7 for

more information.

Figure 19. θ

vs Thermal Via Count for the TO-263 THIN Package on 4–Layer PCB

Figure 20 shows the thermal performance when the Thin TO-263 is mounted to a two layer PCB where the

copper area is predominately directly under the exposed DAP. .As shown in the figure, increasing the copper

area beyond 1 square inch produces very little improvement.

Figure 20. θ

vs Copper Area for the TO-263 THIN Package

Product Folder Links: LP38513-ADJ