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TS29150
4-5
2003/12 rev. A
Using the calculated values for TR(max) and PD, the
maximum allowable value for the junction to ambient
thermal resistance, θja, can now be found:
θja = TR(max) / PD
IMPORTANT: if the maximum allowable value for is
found to be ≥60
oC/W for the TO-220 package, ≥80 oC/W
for the TO-263 package, no heatsink is needed since
the package alone will dissipate enough heat to satisfy
these requirements. If the calculated value for θja falls
below these limits, a heatsink is required.