Datasheet

LM137, LM337-N
SNVS778D –MAY 1999–REVISED APRIL 2013 www.ti.com
APPLICATION HINTS
When a value for θ
(H−A)
is found using the equation shown, a heatsink must be selected that has a value that is
less than or equal to this number.
HEATSINKING SOT-223 PACKAGE PARTS
The SOT-223 (“DCY”) packages use a copper plane on the PCB and the PCB itself as a heatsink. To optimize
the heat sinking ability of the plane and PCB, solder the tab of the package to the plane.
Figure 9 and Figure 10 show the information for the SOT-223 package. Figure 10 assumes a θ
(J−A)
of 75°C/W for
1 ounce copper and 51°C/W for 2 ounce copper and a maximum junction temperature of 125°C.
Figure 9. θ
(J−A)
vs Copper (2 ounce) Area for the SOT-223 Package
Figure 10. Maximum Power Dissipation vs. T
AMB
for the SOT-223 Package
Please see AN-1028 (literature number SNVA036) for power enhancement techniques to be used with the SOT-
223 package.
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