LP38853_15 datasheet(17/28 Pages) TI

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AMBIENT TEMPERATURE (°C)

–50

–25

100

125

PFM Package

1 Sq Inch of 1 oz. Copper

qJA = 35°C/W

TJ=125°C

TJ < 125°C

LP38853

www.ti.com

SNVS335D – DECEMBER 2006 – REVISED APRIL 2013

Figure 33.

θJA vs Copper (1 Ounce) Area for the

Figure 34. 101Maximum Power Dissipation vs

DDPAK package

Ambient Temperature for the DDPAK Package

Heat-Sinking The SO PowerPAD-8 Package

The LP38853MR package has a

θJA rating of 168°C/W, and a θJC rating of 11°C/W. The θJA rating of 168°C/W

includes the device DAP soldered to an area of 0.008 square inches (0.09 in x 0.09 in) of 1 ounce copper, with

no airflow.

Increasing the copper area soldered to the DAP to 1 square inch of 1 ounce copper, using a dog-bone type

layout, will improve the

θJA rating to 98°C/W. Figure 35 shows that increasing the copper area beyond 1 square

inch produces very little improvement.

Figure 36 shows the maximum allowable power dissipation for the SO PowerPAD-8 package for a range of

ambient temperatures, assuming

θJA is 98°C/W and the maximum junction temperature is 125°C.

Figure 35.

θJA vs Copper (1 Ounce) Area for the SO Figure 36. Maximum Power Dissipation vs Ambient

PowerPAD-8 Package

Temperature for the SO PowerPAD-8 Package

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