LM431: Junction-to-ambient thermal resistance - Test Board Used

Hello TI Team,

Checking the datasheet of part LM431AIM3X/NOPB, I found the R_θJA (Junction-to-ambient thermal resistance) value on section 6.4 Thermal Information. However, it did not mentioned anything about the test board used to measure this value.

There is just a note saying "For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953." 

Could you please advise which JEDEC board was used (1s or 2s2p)?

Regards,

Bruno Schmitt.