LP3874-ADJ Datasheet, PDF (12/15 Pages) National Semiconductor (TI) – 0.8A Fast Ultra Low Dropout Linear Regulators

Application Hints (Continued)
HEATSINKING SOT223-5 PACKAGE
Figure 3 shows a curve for the θ_JA of SOT-223 package for
different copper area sizes, using a typical PCB with 1 ounce
copper and no solder mask over the copper area for heat
sinking.
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FIGURE 4. SCENARIO A, θ_JA = 148˚C/W
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FIGURE 3. θ_JA vs Copper(1 Ounce) Area for SOT-223
package
The following figures show different layout scenarios for
SOT-223 package.
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FIGURE 5. SCENARIO B, θ_JA = 125˚C/W
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