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 , 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

5.1 ΨJB Application

ΨJB can allow the system designer to measure the board temperature with a fine gauge thermocouple and back-calculate the junction temperature using Equation 9. Note that ΨJB is close to Rθ(JB), as the PCB dissipates 75%–95% of the heat of a device.

Equation 9. GUID-0EED33A4-BAD6-4EF3-9A7B-9CE687A4B618-low.gif

Measurement of ΨJB is defined by JESD51-6. Care should be taken with the selection of the thermocouple type, gauge and dressing of the thermocouple across the PCB in a similar fashion to the thermocouple intended to measure case temperature for ΨJT measurements. As with ΨJT measurements, an IR camera or fiber optic probe can be used to measure the PCB temperature. However, an IR thermal gun is not appropriate due to the small spot size to be imaged.