I have been Searching for power mosfets for designing an inverter. One crucial parameter I was looking for is the Rds_on relationship with junction temperature. Other manufacturers (infineon, Irf, ST) seem to provide a graph of Rds_on with respect to Junction temperature. Oddly toshiba's datasheet seems to specify the Rds_on wrt to ambient temperature. enter image description here

The above graph was taken from TK65A10N1 mosfet's datasheet. All toshiba's mosfets seem to specify their temperature dependence like this.

How would one extract information about Rds_on wrt to Junction temperature. A case can be made that using thermal impedances the junction temperature could be extracted. But power dissipation is not known.

Any Ideas?


1 Answer 1


It's stated as a pulse test, so you can assume Tj \$\approx\$ Ta.

  • \$\begingroup\$ Could you elaborate please? \$\endgroup\$ Feb 26, 2023 at 6:10
  • 1
    \$\begingroup\$ The pulse is assumed to be short enough that the junction temperature remains at ambient (close enough). \$\endgroup\$ Feb 26, 2023 at 6:11

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