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Original question:

TLK10232: Package Theta-JA and Theta-JC and Heatsinks

TLK10232: theta-JC

Bill Bynum
Prodigy 40 points
Part Number: TLK10232

Hi, 

Looking at SPRA953C and the TLK10232 datasheet, equation 5 requires RΘJC for the calculation.

Table 10-1. Package Thermal Characteristics

JEDEC STANDARD BOARD

PARAMETER

VALUE

ΘJA

Theta-JA

25.5

ΨJT

Psi-JT

1.8

ΨJB

Psi-JB

13.7

CUSTOM TYPICAL APPLICATION BOARD(1)

ΘJA

Theta-JA

24.5

ΨJT

Psi-JT

0.9

ΨJB

Psi-JB

11

I can pull RΘCS from thermal grease or gap pad datasheets and RΘSA from a heatsink datasheet, but there isn't a way to calculate RΘJC from φJT or φJB as far as I know.

Thanks,

--Bill

  • 0
    TI__Genius 17055 points

    Hi Bill,

    That's correct, theta-JC cannot be calculated from psi-JT or psi-JB. Psi-JT is calculated with the assumption that the quantity of heat flowing from the die to the top of the package is the total power of the device. Theta-JC theoretically would be calculated using the actual quantity of heat flowing, which is less than total device power, but this measurement is often unknown so theta-JC cannot be calculated. This means theta-JC needs to be measured by forcing almost all of the device power through the top of the package, which is typically done using a copper cold plate.

    Unfortunately we do not have validation data characterizing theta-JC for TLK10232. If you are interested in measuring theta-JC, I recommend following the procedure outlined in the Copper Cold Plate R_theta-JC Measurement section of SPRA953C.

    Best,

    Lucas

  • 0 in reply to Lucas Wolter
    Prodigy 40 points

    Hi Lucas,

    OK. I appreciate you looking into this.

    Thanks,

    --Bill