LP3853 datasheet(15/18 Pages) NSC

Il numero della parte	LP3853

Spiegazioni elettronici	3A Fast Response Ultra Low Dropout Linear Regulators

PDF	18 Pages

Scroll/Zoom	100%

Produttore elettronici	NSC [National Semiconductor (TI)]

Homepage	http://www.national.com

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15 / 18 page

Application Hints (Continued)

HEATSINKING TO-263 PACKAGE

The TO-263 package uses the copper plane on the PCB as

a heatsink. The tab of these packages are soldered to the

copper plane for heat sinking. Figure 5 shows a curve for the

JA of TO-263 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.

As shown in the figure, increasing the copper area beyond 1

square inch produces very little improvement. The minimum

value for

JA for the TO-263 package mounted to a PCB is

32˚C/W.

Figure 6 shows the maximum allowable power dissipation

for TO-263 packages for different ambient temperatures,

assuming

JA is 35˚C/W and the maximum junction tempera-

ture is 125˚C.

20030932

FIGURE 5.

JA vs Copper (1 Ounce) Area for TO-263

package

20030933

FIGURE 6. Maximum power dissipation vs ambient

temperature for TO-263 package

LP3853 Scheda tecnica(PDF) 15 Page - National Semiconductor (TI)