What is thermal resistance of SMD7530 similar to this photo (Or typical LED in this type):

enter image description here

With this datasheet:

Datasheet for SMD7530

I cannot find any thermal resistance in it's datasheet.

  • \$\begingroup\$ I would contact the manufacturer for better information if I were you. \$\endgroup\$
    – stefandz
    Sep 8, 2015 at 16:23
  • \$\begingroup\$ It's a crappy data sheet and that usually means a crappy supplier that neither knows the market nor cares. \$\endgroup\$
    – Andy aka
    Sep 8, 2015 at 16:43
  • \$\begingroup\$ But he might try at least. \$\endgroup\$
    – Looongcat
    Sep 8, 2015 at 19:37
  • \$\begingroup\$ Also you can find several LEDs from another manufacturers, but with same package, and compare their characteristics. If it's similar i think you can approximate it as 0.8*<typ.value> \$\endgroup\$
    – Looongcat
    Sep 8, 2015 at 19:39

1 Answer 1


Since the maximum junction temperature is 120°C and the maximum current is 150mA, you can guess that the thermal resistance is such that 95°C of rise occurs at 0.465W given the typical forward voltage is 3.1V, so about 204K/W.

However that number is essentially useless since you don't know anything about the conditions under which that number is valid. It could be 20 x 20mm of aluminum core PCB, for example. If you assume that number and use FR-4 with modest amounts of thin copper, the LED life may be greatly foreshortened.


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