SPRA953D December   2003  – March 2024 CSD13201W10 , CSD13202Q2 , CSD13302W , CSD13303W1015 , CSD13306W , CSD13380F3 , CSD13381F4 , CSD13383F4 , CSD13385F5 , CSD15380F3 , CSD15571Q2 , CSD16301Q2 , CSD16321Q5 , CSD16322Q5 , CSD16323Q3 , CSD16325Q5 , CSD16327Q3 , CSD16340Q3 , CSD16342Q5A , CSD16401Q5 , CSD16403Q5A , CSD16404Q5A , CSD16406Q3 , CSD16407Q5 , CSD16408Q5 , CSD16409Q3 , CSD16410Q5A , CSD16411Q3 , CSD16412Q5A , CSD16413Q5A , CSD16414Q5 , CSD16415Q5 , CSD16556Q5B , CSD16570Q5B , CSD17301Q5A , CSD17302Q5A , CSD17303Q5 , CSD17304Q3 , CSD17305Q5A , CSD17306Q5A , CSD17307Q5A , CSD17308Q3 , CSD17309Q3 , CSD17310Q5A , CSD17311Q5 , CSD17312Q5 , CSD17313Q2 , CSD17318Q2 , CSD17322Q5A , CSD17327Q5A , CSD17381F4 , CSD17382F4 , CSD17483F4 , CSD17484F4 , CSD17501Q5A , CSD17505Q5A , CSD17506Q5A , CSD17507Q5A , CSD17510Q5A , CSD17522Q5A , CSD17527Q5A , CSD17551Q3A , CSD17551Q5A , CSD17552Q3A , CSD17552Q5A , CSD17553Q5A , CSD17555Q5A , CSD17556Q5B , CSD17559Q5 , CSD17570Q5B , CSD17571Q2 , CSD17573Q5B , CSD17575Q3 , CSD17576Q5B , CSD17577Q3A , CSD17577Q5A , CSD17578Q3A , CSD17578Q5A , CSD17579Q3A , CSD17579Q5A , CSD17581Q3A , CSD17581Q5A , CSD17585F5 , CSD18501Q5A , CSD18502KCS , CSD18502Q5B , CSD18503KCS , CSD18503Q5A , CSD18504KCS , CSD18504Q5A , CSD18509Q5B , CSD18510KCS , CSD18510KTT , CSD18510Q5B , CSD18511KCS , CSD18511KTT , CSD18511Q5A , CSD18512Q5B , CSD18513Q5A , CSD18514Q5A , CSD18531Q5A , CSD18532KCS , CSD18532NQ5B , CSD18532Q5B , CSD18533KCS , CSD18533Q5A , CSD18534KCS , CSD18534Q5A , CSD18535KCS , CSD18535KTT , CSD18536KCS , CSD18536KTT , CSD18537NKCS , CSD18537NQ5A , CSD18540Q5B , CSD18541F5 , CSD18542KCS , CSD18542KTT , CSD18543Q3A , CSD18563Q5A , CSD19501KCS , CSD19502Q5B , CSD19503KCS , CSD19505KCS , CSD19505KTT , CSD19506KCS , CSD19506KTT , CSD19531KCS , CSD19531Q5A , CSD19532KTT , CSD19532Q5B , CSD19533KCS , CSD19533Q5A , CSD19534KCS , CSD19534Q5A , CSD19535KCS , CSD19535KTT , CSD19536KCS , CSD19536KTT , CSD19537Q3 , CSD19538Q2 , CSD19538Q3A , CSD22202W15 , CSD22204W , CSD22205L , CSD22206W , CSD23202W10 , CSD23203W , CSD23280F3 , CSD23285F5 , CSD23381F4 , CSD23382F4 , CSD25202W15 , CSD25211W1015 , CSD25213W10 , CSD25304W1015 , CSD25310Q2 , CSD25402Q3A , CSD25404Q3 , CSD25480F3 , CSD25481F4 , CSD25483F4 , CSD25484F4 , CSD25485F5 , CSD25501F3 , CSD75207W15 , CSD75208W1015 , CSD83325L , CSD85301Q2 , CSD85302L , CSD85312Q3E , CSD86311W1723 , CSD86330Q3D , CSD86336Q3D , CSD86350Q5D , CSD86356Q5D , CSD86360Q5D , CSD87312Q3E , CSD87313DMS , CSD87330Q3D , CSD87331Q3D , CSD87333Q3D , CSD87334Q3D , CSD87335Q3D , CSD87350Q5D , CSD87351Q5D , CSD87351ZQ5D , CSD87352Q5D , CSD87353Q5D , CSD87355Q5D , CSD87381P , CSD87384M , CSD87501L , CSD87502Q2 , CSD87503Q3E , CSD87588N , CSD88537ND , CSD88539ND , CSD88584Q5DC , CSD88599Q5DC , DS90UH940N-Q1 , LM22670 , LM22671 , LM22671-Q1 , LM22672 , LM22672-Q1 , LM22673 , LM22673-Q1 , LM22674 , LM22674-Q1 , LM22675 , LM22675-Q1 , LM22676 , LM22676-Q1 , LM22677 , LM22677-Q1 , LM22678 , LM22678-Q1 , LM22679 , LM22679-Q1 , LM22680 , LM22680-Q1 , LM25574 , LM25574-Q1 , LM25575 , LM25575-Q1 , LM25576 , LM25576-Q1 , LM2574 , LM2574HV , LM2575 , LM2575HV , LM2576 , LM2576HV , LM2577 , LM2585 , LM2586 , LM2587 , LM2588 , LM2590HV , LM2591HV , LM2592HV , LM2593HV , LM2594 , LM2594HV , LM2595 , LM2596 , LM2597 , LM2597HV , LM2598 , LM2599 , LM2670 , LM2671 , LM2672 , LM2673 , LM2674 , LM2675 , LM2676 , LM2677 , LM2678 , LM2679 , LM2698 , LM2736 , LM2840 , LM2840-Q1 , LM2841 , LM2841-Q1 , LM2842 , LM2842-Q1 , LM3100 , LM3102 , LM3102-Q1 , LM3103 , LM3691 , LM43600 , LM43601 , LM43602 , LM43603 , LM46000 , LM46001 , LM46002 , LM5574 , LM5574-Q1 , LM5575 , LM5575-Q1 , LM5576 , LM5576-Q1 , LMR10510 , LMR10515 , LMR10520 , LMR10530 , LMR12007 , LMR12010 , LMR12015 , LMR12020 , LMR14203 , LMR14206 , LMR16006 , LMR24210 , LMR24220 , LMR61428 , LMR62014 , LMR62421 , LMR64010 , LMR70503 , SN74SSQE32882 , SN74SSQEA32882 , TMS320C28341 , TMS320C28342 , TMS320C28343 , TMS320C28343-Q1 , TMS320C28344 , TMS320C28345 , TMS320C28346 , TMS320C28346-Q1 , TMS320F280021 , TMS320F280021-Q1 , TMS320F280023 , TMS320F280023-Q1 , TMS320F280023C , TMS320F280025 , TMS320F280025-Q1 , TMS320F280025C , TMS320F280025C-Q1 , TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1 , TMS320F2801 , TMS320F2801-Q1 , TMS320F2802-Q1 , TMS320F28020 , TMS320F28021 , TMS320F28022 , TMS320F28022-Q1 , TMS320F28023 , TMS320F28023-Q1 , TMS320F28026 , TMS320F28026-Q1 , TMS320F28026F , TMS320F28027 , TMS320F28027-Q1 , TMS320F28027F , TMS320F28027F-Q1 , TMS320F28030 , TMS320F28030-Q1 , TMS320F28031 , TMS320F28031-Q1 , TMS320F28032 , TMS320F28032-Q1 , TMS320F28033 , TMS320F28033-Q1 , TMS320F28034 , TMS320F28034-Q1 , TMS320F28035 , TMS320F28035-Q1 , TMS320F28050 , TMS320F28051 , TMS320F28052 , TMS320F28052-Q1 , TMS320F28052F , TMS320F28052F-Q1 , TMS320F28052M , TMS320F28052M-Q1 , TMS320F28053 , TMS320F28054 , TMS320F28054-Q1 , TMS320F28054F , TMS320F28054F-Q1 , TMS320F28054M , TMS320F28054M-Q1 , TMS320F28055 , TMS320F2806 , TMS320F2806-Q1 , TMS320F28062 , TMS320F28062-Q1 , TMS320F28062F , TMS320F28062F-Q1 , TMS320F28063 , TMS320F28064 , TMS320F28065 , TMS320F28066 , TMS320F28066-Q1 , TMS320F28067 , TMS320F28067-Q1 , TMS320F28068F , TMS320F28068M , TMS320F28069 , TMS320F28069-Q1 , TMS320F28069F , TMS320F28069F-Q1 , TMS320F28069M , TMS320F28069M-Q1 , TMS320F28075 , TMS320F28075-Q1 , TMS320F2808 , TMS320F2808-Q1 , TMS320F2810 , TMS320F2810-Q1 , TMS320F2811 , TMS320F2811-Q1 , TMS320F2812 , TMS320F2812-Q1 , TMS320F28232 , TMS320F28232-Q1 , TMS320F28234 , TMS320F28234-Q1 , TMS320F28235 , TMS320F28235-Q1 , TMS320F28332 , TMS320F28333 , TMS320F28334 , TMS320F28335 , TMS320F28335-Q1 , TMS320F28374D , TMS320F28374S , TMS320F28375D , TMS320F28375S , TMS320F28375S-Q1 , TMS320F28376D , TMS320F28376S , TMS320F28377D , TMS320F28377D-Q1 , TMS320F28377S , TMS320F28377S-Q1 , TMS320F28379D , TMS320F28379D-Q1 , TMS320F28379S , TMS320LF2401A , TMS320LF2402A , TMS320LF2403A , TMS320LF2406A , TMS320LF2407A , TPS54020 , TPS54218 , TPS54318 , TPS54320 , TPS54418 , TPS54478 , TPS54618 , TPS54622 , TPS54623 , TPS54678 , TPS56121 , TPS56221

 

  1.   1
  2.   Semiconductor and IC Package Thermal Metrics
  3.   Trademarks
  4. 1RθJA Junction-to-Ambient and RθJMA Junction-to-Moving Air
    1. 1.1 Usage
    2. 1.2 Test Card Impact
    3. 1.3 Die Size Impact
    4. 1.4 Internal Package Geometrical Configuration
    5. 1.5 Altitude
    6. 1.6 Ambient Temperature
    7. 1.7 Power Dissipation
    8. 1.8 RθJA Effective
  5. 2RθJC Junction-to-Case
    1. 2.1 Copper (Cu) Cold Plate RθJC Measurement
    2. 2.2 RθJC Application
    3. 2.3 Rθ(CS)
    4. 2.4 RθJC(top) and RθJC(bot)
  6. 3ΨJT, Junction to Top of Package
    1. 3.1 Case Temperature Measurement
    2. 3.2 ΨJT vs RθJC When Using Heat Sinks
  7. 4Rθ(JB) Junction-To-Board
    1. 4.1 Rθ(JB) Measurement Method
  8. 5ΨJB Junction-to-Board Characterization Parameter
    1. 5.1 ΨJB Application
  9. 6Industrial and Commercial Temperature Ranges
  10. 7Miscellaneous Definitions
  11. 8References
  12. 9Revision History

2.4 RθJC(top) and RθJC(bot)

Some packages have mechanisms such as heat slugs or exposed pads to remove heat from the top, bottom, or both surfaces of the package. When only a single surface is used for heat removal, this is the surface that would be used for RθJC based on the EIA/JESD51-1 specification. Sometimes, designers wish also to include heat sinks on the top of the package, even if the exposed pads are soldered to the PCB. In such instances, it is appropriate to define RθJC(top) and RθJC(bot) to avoid confusion over which surface is being referenced. The top surface is the surface of the package facing away from the PCB, whereas the bottom surface is the surface of the package facing toward the PCB. When RθJC(bot) is to be measured, a special PCB is constructed with a cutout to allow contact between the bottom package surface and Cu cold plate. When in contact with the Cu cold plate, the temperature taken at the bottom surface of the package becomes the case temperature that is used in calculating the temperature delta between the case and junction temperature.

It should be noted that Texas Instruments has at times used the nomenclature of Rθ(JP), or junction-to-pad, to refer to the thermal resistance between the junction and exposed pad of the package. This nomenclature has been used regardless of whether the pad was exposed on the top or bottom of the package.