1、 IEC TR 63091 Edition 1.0 2017-05 TECHNICAL REPORT Study for the derating curve of surface mount fixed resistors Derating curves based on terminal part temperature IEC TR 63091:2017-05(en) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2017 IEC, Geneva, Switzerland All rights reserved. Unless oth
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10、h/csc If you wish to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csciec.ch. IEC TR 63091 Edition 1.0 2017-05 TECHNICAL REPORT Study for the derating curve of surface mount fixed resistors Derating curves based on terminal part tem
11、perature INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 31.040.10 ISBN 978-2-8322-4368-8 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. 2 IEC TR 63091:2017 IEC 2017 CONTENTS FOREWORD . 7 INTRO
12、DUCTION . 9 1 Scope 10 2 Normative references 10 3 Terms and definitions 10 4 Study for the derating curve of surface mount fixed resistors . 11 4.1 General . 11 4.2 Using the derating curve based on the terminal part temperature 12 4.3 Measuring method of the terminal part temperature of the SMD re
13、sistor . 13 4.4 Measuring method of the thermal resistance R th shs-tfrom the terminal part to the surface hotspot . 19 4.5 Conclusions 21 Annex A (informative) Background of the establishment of the derating curve based on ambient temperature 22 A.1 Tracing the history of the mounting and heat diss
14、ipation figuration of resistors 22 A.2 How to establish the high temperature slope part of the derating curve . 24 A.2.1 General . 24 A.2.2 Derating curve for the semiconductors . 26 A.2.3 Derating curve for resistors 29 Annex B (informative) The temperature rise of SMD resistors and the influence o
15、f the printed circuit board 40 B.1 Temperature rise of SMD resistors 40 B.2 The influence of the printed circuit boards . 45 Annex C (informative) The influence of the number of resistors mounted on the test board 49 C.1 General . 49 C.2 The influence of the number of resistors mounted on the test b
16、oard 49 C.3 The delay of correspondence for current products with nonstandard dimensions . 51 Annex D (informative) Influence of the air flow in the test chamber 52 D.1 General . 52 D.2 Influence of the wind speed 52 Annex E (informative) Validity of the new derating curve 60 E.1 Suggestion for esta
17、blishing the derating curve based on the terminal part temperature 60 E.2 Conclusion 65 Annex F (informative) The thermal resistance of SMD resistors . 67 Annex G (informative) How to measure the surface hotspot temperature . 72 G.1 Target of the measurement . 72 G.2 Recommended measuring equipment
18、. 72 G.3 Points to be careful when measuring the surface hotspot of the resistor with an infrared thermograph 72 G.3.1 General . 72 G.3.2 Spatial resolution and accuracy of peak temperature measurement . 73 G.3.3 Influence of the angle of the measurement target normal line and the infrared thermogra
19、ph light axis 75 IEC TR 63091:2017 IEC 2017 3 Annex H (informative) How the resistor manufacturers measure the thermal resistance of resistors 79 H.1 The measuring system 79 H.2 Definition of the two kinds of temperatures 80 H.3 Errors in the measurement 83 Annex I (informative) Measurement method o
20、f the terminal part temperature of the SMD resistors . 88 I.1 Measuring method using an infrared thermograph . 88 I.2 Measuring method using the thermocouple . 89 I.3 Estimating the error range of the temperature measurement using the thermal resistance of the thermocouple . 90 I.3.1 General . 90 I.
21、3.2 When using the type T thermocouples . 97 I.4 Thermal resistance of the board 97 I.5 Conclusion of this annex . 100 Annex J (informative) The variation of the heat dissipation fraction caused by the difference between the resistor and its mounting configuration . 101 J.1 Heat dissipation ratio of
22、 cylindrical resistors wired in the air 101 J.2 Heat dissipation ratio of SMD resistors mounted on the board 102 J.3 Heat dissipation ratio of the cylindrical resistors mounted on the through- hole printed board . 104 Annex K (informative) Influence of airflow on SMD resistors 105 K.1 General . 105
23、K.2 Measurement system 105 K.3 Test results (orthogonal) . 106 K.4 Test results (parallel) 110 Annex L (informative) The influence of the spatial resolution of the thermograph . 115 L.1 The application for using the thermograph when measuring the temperature of the SMD resistor . 115 L.2 The relatio
24、n between the minimum area that the accurate temperature could be measured and the pixel magnification percentage 115 L.3 Example of the RR1608M SMD resistor hotspots actual measurement . 120 L.4 Conclusion 121 Annex M (informative) Future subjects . 122 Bibliography 123 Figure 1 Existing derating c
25、urve based on ambient temperature 12 Figure 2 Suggested derating curve based on terminal temperature 12 Figure 3 Attachment position of the thermocouple when measuring the temperature of the terminal part 13 Figure 4 Attaching type K thermocouples . 14 Figure 5 Wiring routing of the thermocouple . 1
26、5 Figure 6 The true value and the actual measured value of the terminal part temperature 16 Figure 7 Thermal resistance R th eqof the FR4 single side board (thickness 1,6 mm) 17 Figure 8 Length that cause the heat dissipation and the thermal resistance of the type-K thermocouple (calculated) 18 Figu
27、re 9 Example of calculation of the measurement error T caused by the heat dissipation of the thermocouple 19 4 IEC TR 63091:2017 IEC 2017 Figure 10 Recommended measurement system of T shsand T tfor calculating R th shs-t. 20 Figure A.1 Wired in the air using the lug terminal . 22 Figure A.2 Heat pat
28、h when wired in the air using the lug terminal 23 Figure A.3 Test condition for resistors with category power 0 W . 24 Figure A.4 Test condition for resistors with category power other than 0 W 25 Figure A.5 Example of reviewing the derating curve . 26 Figure A.6 T j , T cand R th j-cof transistors
29、27 Figure A.7 Derating curves for transistors 28 Figure A.8 Trajectory of T jwhen P is reduced according to the derating curve . 29 Figure A.9 Leaded resistors with small temperature rise 30 Figure A.10 Leaded resistors with large temperature rise . 31 Figure A.11 Trajectory of T hsfor the lead wire
30、 resistors with small temperature rise 31 Figure A.12 Trajectory of T hsfor the lead wire resistors with large temperature rise 33 Figure A.13 Trajectory of T hsfor resistors with category power other than 0 W 34 Figure A.14 T spand MAT for lead wire resistors with large temperature rise 35 Figure A
31、.15 T spand MAT for lead wire resistors with small temperature rise . 36 Figure A.16 Resistors for which the hotspot is the thermally sensitive point . 37 Figure A.17 Resistor that have derating curve similar to the semiconductor . 38 Figure B.1 Temperature distribution of the SMD resistors mounted
32、on the board . 41 Figure B.2 Temperature rise of the SMD resistors from the ambient temperature . 42 Figure B.3 Measurement system layout and board dimension 43 Figure B.4 Temperature rise of RR2012M (thickness 35 m, 0 ,25 W applied) 44 Figure B.5 Temperature rise of RR2012M (thickness 70 m, 0,25 W
33、applied) 45 Figure B.6 Trajectory of the terminal part and hotspot temperature of the SMD resistors 46 Figure B.7 Operating temperature of the resistor on the board with narrow patterns. 47 Figure C.1 Test board compliant with the IEC standard for RR1608M 50 Figure C.2 Relation between the number of
34、 samples and the surface hotspot temperature rise . 50 Figure C.3 Infrared thermograph image in the same scale when power is applied to 5 samples and 20 samples . 51 Figure D.1 Wind speed and the terminal part temperature rise of the RR6332M . 53 Figure D.2 Test system for the natural convection flo
35、w 53 Figure D.3 Observing the influence of the agitation wind in the test chamber . 55 Figure D.4 Wind speed and the terminal part temperature rise of the RR5025M . 56 Figure D.5 Wind speed and the terminal part temperature rise of the RR3225M . 56 Figure D.6 Wind speed and the terminal part tempera
36、ture rise of the RR3216M . 57 Figure D.7 Wind speed and the terminal part temperature rise of the RR2012M . 57 Figure D.8 Wind speed and the terminal part temperature rise of the RR1608M . 58 Figure D.9 Wind speed and the terminal part temperature rise of the RR1005M . 58 Figure E.1 Derating conditi
37、ons of SMD resistors on the resistor manufacturer test board 60 Figure E.2 New derating curve provided by the resistor manufacturer to the electric/electronic designers 63 IEC TR 63091:2017 IEC 2017 5 Figure E.3 Derating curve based on the terminal part temperature . 64 Figure E.4 Derating curve bas
38、ed on the terminal part temperature . 65 Figure F.1 Definition of the thermal resistance in a strict sense 68 Figure F.2 Thermal resistance of the resistor . 69 Figure G.1 Difference of the measured hotspot temperature caused by the spatial resolution 74 Figure G.2 Measuring system for the error cau
39、sed by the angle . 76 Figure G.3 Error caused by the angle of the optical axis and the target surface (natural convection) 77 Figure G.4 Error caused by the angle of the optical axis and the target surface (0,3 m/s air ventilation from the side) . 77 Figure H.1 Measuring system for calculating the t
40、hermal resistance between the surface hotspot and the terminal part 80 Figure H.2 Simulation model 81 Figure H.3 Temperature distribution of the copper block surface (calculated) . 84 Figure H.4 Isothermal line of the fillet part (calculated) 86 Figure I.1 Temperature drop caused by the attached the
41、rmocouple . 89 Figure I.2 Example of the printed board . 90 Figure I.3 Printed board shown with the thermal network . 91 Figure I.4 Equivalent circuit of the printed board shown with the thermal network . 92 Figure I.5 Equivalent circuit when the thermocouple is connected 93 Figure I.6 Ambient tempe
42、rature and the space need for the heat dissipation of the thermocouple 94 Figure I.7 Equivalent circuit when the thermocouple is connected 95 Figure I.8 Length that causes the heat dissipation and the thermal resistance of the type K thermocouple (calculated) 96 Figure I.9 Length that cause the heat
43、 dissipation and the thermal resistance of the type T thermocouple (calculated) 97 Figure I.10 Thermal resistance R th eqof the FR4 single side board (thickness 1,6 mm) 98 Figure I.11 Calculating the thermal resistance of the board from the fillet side 99 Figure J.1 Simulation model of the lead wire
44、 resistors wired in the air 101 Figure J.2 Heat dissipation ratio of the leaded cylindrical resistors (calculated) . 102 Figure J.3 Measurement system of the heat dissipation ratio of SMD resistors mounted on the board . 103 Figure K.1 Measurement system 106 Figure K.2 Relationship between the termi
45、nal part temperature rise and the wind speed for the RR6332M (orthogonal) 107 Figure K.3 Relationship between the terminal part temperature rise and the wind speed for the RR5025M (orthogonal) 107 Figure K.4 Relationship between the terminal part temperature rise and the wind speed for the RR3225M (
46、orthogonal) 108 Figure K.5 Relationship between the terminal part temperature rise and the wind speed for the RR3216M (orthogonal) 108 Figure K.6 Relationship between the terminal part temperature rise and the wind speed for the RR2012M (orthogonal) 109 Figure K.7 Relationship between the terminal p
47、art temperature rise and the wind speed for the RR1608M (orthogonal) 109 6 IEC TR 63091:2017 IEC 2017 Figure K.8 Relationship between the terminal part temperature rise and the wind speed for the RR1005M (orthogonal) 110 Figure K.9 Relationship between the terminal part temperature rise and the wind
48、 speed for the RR6332M (parallel) . 111 Figure K.10 Relationship between the terminal part temperature rise and the wind speed for the RR5025M (parallel) . 111 Figure K.11 Relationship between the terminal part temperature rise and the wind speed for the RR3225M (parallel) . 112 Figure K.12 Relation
49、ship between the terminal part temperature rise and the wind speed for the RR3216M (parallel) . 112 Figure K.13 Relationship between the terminal part temperature rise and the wind speed for the RR2012M (parallel) . 113 Figure K.14 Relationship between the terminal part temperature rise and the wind speed for the RR1608M (parallel) . 113 Figure K.15 Relationship betwe
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