Datasheet

LM117, LM317A, LM317-N
www.ti.com SNVS774N –MAY 2004–REVISED AUGUST 2013
Figure 26. θ
(J−A)
vs Copper (2 ounce) Area for the SOT-223 Package
Figure 27. Maximum Power Dissipation vs T
AMB
for the SOT-223 Package
Heatsinking the TO-263 (KTT) Package
Figure 28 shows for the TO-263 the measured values of θ
(J−A)
for different copper area sizes using a typical PCB
with 1 ounce copper and no solder mask over the copper area used for heatsinking.
As shown in Figure 28, increasing the copper area beyond 1 square inch produces very little improvement. It
should also be observed that the minimum value of θ
(J−A)
for the TO-263 package mounted to a PCB is 32°C/W.
Figure 28. θ
(J−A)
vs Copper (1 ounce) Area for the TO-263 Package
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