2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Chan, CY

Yung, KC

PolyU Institutional Repository

 ? 12?                                      ? ? ? ? ? ? ?                                     Vol.24 No.122005? 12?                                   ELECTRONIC COMPONENTS & MATERIALS                                      Dec. 2005 ???????????? ??????? ???????????????????  ?????? ??: ???????????????????? PCB???????????????? PCB?????????????????????????? PCB?????????????????????????????????????????????????????? PCB ??????????? PCB ???????????????????????????????????? PCB????????? ???????????PCB????????????????? TN406  ??????A  ?????1001-2028?2005?12-0061-03 Investigation of Thermal Characteristics of Embedded Resistors Chen C Y, Yung Winco K C  (Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong)?Abstract: Thermal characteristics of embedded resistors in PCB (Printed Circuit Board) were studied. From the investigations of powers and surface areas of embedded resistors, the parse function of temperature rise in PCB was formulated. The differences in temperature rises against various locations in a PCB with embedded resistors also were calculated. From the analysis on relationships between single resistor and multi resistors, the calculation method of temperature rise in PCB with multi embedded resistors are presented. It was observed that an embedded resistor with large power should be placed at the center of a board and each heat source should maintain a distance among each other. Key words: electronic technology; embedded resistor; PCB; thermal characteristics; design rules  ???????????????? PCB????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ????????????????????????? PCB?????????????????????? PCB???????????????????????????????????????PCB?????????????????????????????????????????[1,2]???????????????????????????????????????????????????????????????????? PCB????????????? PCB ????????????????????? ???????????????????????????????????????? PCB?????????????????????? PCB??????????????????? 1 ???? ? PCB ?????????????????????????????????????????????PCB???????????????????????????????????????P??? RIP R2=                  (1) ???IR?????????R ??????????????? PkT 12 −=∇               (2) ?  ?  ?  RELIABILITY ?????2005-08-12    ???????? ??????????? CRG???????G-T533???????????1961????????????????????????????Tel: (852)27664980?E-mail: jinzhiling@tom.com ??DOI:10.14106/j.cnki.1001-2028.2005.12.01962                                         ?  ?  ?  ?  ?  ?  ?                                    2005?  ???k ???????[W/(m·K)]?????????? PCB ?????????????????PCB???????????????????????????PCB?????????? )( ∞−=∆= tthAThAQ w         (3) ???h?????????[150 W/(m2·K)]?A????(m2)?tw? PCB??????(?)?t∞???????(?)? ???????????????????????????????????????????????????????????? ANSYS? 2  PCB??????????????????? ???????????????????????????? PCB ?????????PCB ????? 25.4 mm×25.4 mm×5.1 mm?PCB?????FR?4?????? 1.7 W/ (m·K)?PCB??????? 27??????????? 50 W/ (m2·K)? 2.1 ??????? ????????? 2 mm×1 mm×0.01 mm???? PCB??????????????? 5 mW???????????? 1 170 W/m2??????????????????? 1??? PCB???????          t / ? ? 1  PCB??????? Fig.1  Temperature contours in PCB ?????? 27.03~27.584???????????????????????? PCB??????? 27???? 27.03??????????????????????? 2.2 ??????? PCB????????????????????????????????????????????????????? 4 mm×1 mm×0.2 mm (???)? 2 mm×1 mm×0.2 mm (???)?????????? 0.05? 5 000 mW?????????? ∆{t}? = 0.061 {P}mw + 0.062 79  (???)   (4) ∆{t}? = 0.09 {P}mw– 0.012 83    (???)   (5) ????? P???? mW?? ∆t = kP + d                (6) PCB ???????????????????????????????(4)??????? 2 ???????????????????????? PCB??????????????? PCB???????????????????????(6)???         ? 2  PCB?????????????? Fig.2  Temperature rise in PCB vs the power of the embedded resistor 2.3 ??????????? ?????????????????????? 5 mW??????????????????????????????? ????????? 0.2 mm×0.2 mm×0.2 mm?0.4 mm×0.4 mm×0.4 mm?0.6 mm×0.6 mm×0.6 mm?0.8 mm×0.8 mm×0.8 mm?1.0 mm×1.0 mm×1.0 mm?1.2 mm×1.2 mm×1.2 mm?1.4 mm×1.4 mm×1.4 mm?1.6 mm×1.6 mm×1.6 mm?1.8 mm×1.8 mm×1.8 mm???? ? 3 ??? PCB ?????????? S ???????????????????????????????????????????         ? 3  PCB??????????????? Fig.3  Temperature rise vs the embedded resistor surface area 477.043.3 −=∆ Set               (7) ????(6)???????????????? 477.026.6 −=∆ PSt             (8) ???PCB?????????????????????? αβ −=∆ PSt                (9) ???α ?β  ? PCB???????????????? ?? 27.584??? 27.03?     1×104   1×105    1×106   1×107????? / mm2 1×1001×10–11×10–2?? / ? ??????0.01       1.00       100.00   10 000.00P / mW 1 000.00010.0000.1000.001?? / ?  ? 12 ?                                                                                                    63 ?????????????????? PCB??????????? 3 PCB????????????? PCB ????????????????????????????[1]??????????????????? 30%????????????????????PCB????????????????∆t?? PCB ????????????∆t ????????? PCB ??????????? PCB ??????????????????????? ? 4?????????PCB???????????????????????????????         ? 4  PCB??????????????? Fig.4  Temperature rise in PCB from center to surface 4 ????? ? PCB??????????????????????????????????????????????????????????????????????????????????? PCB????????????????? ??? PCB?????? 1????????????????? 5 ???????????? 2 mm×1 mm×0.01 mm????????? 20 mm?         ? 5  PCB????????????????? Fig.5  Temperature contours of two embedded resistors in PCB ? 5 ??? PCB ???????????????????????????????????????????????? 0.45??? 5???????????????????????????????????????????? PCB???????????????????? ? 6???????? PCB??????????????PCB???????∆t????????????????∆ti????i??????? ∑=∆=∆niitt1                 (10) n??????????      ?PCB?????????????????????????? ? 6  ???? PCB???? Fig.6  Temperature contours of multi embedded resistors in PCB 5 PCB??????????? PCB??????????????????????????????? n??????? PCB???????????????? ????????????????????????????????????????????????PCB????∆t???????????????????∆tmax? ????????????????????????????PCB?????????????????????????????????????????????????????? PCB??????????????????1??????????????????2????????????????? PCB?????? 6 ?? ???PCB???????????????PCB???????????????????????????????????????????????????????????????????? PCB?????????????????????????PCB?????????????????? ????????????????????????????????????????????? ????? [1] Stubbs D M, Pulko S H, Wilkinson A J. An investigation of the sensitivity of embedded passive component temperatures to PCB structure [J]. IEEE Trans Comp Packag Tchnol, 2002, 25(4): 701–705. [2] Rao Y, Wong C P, Qu J. Electrical and mechanical modeling of embedded capacitors [A]. 1999 International Symposium on Advanced Packaging Materials [C]. 1999.  ??????? ?? / ? 0      4      6      8      10     12 ????? PCBA???? / mm 0.5050.5000.4950.4900.4850.4800.4750.4700.4650.4600.4550.45027.4527.4027.3527.3027.2527.2027.1527.1027.0527.00?? / ? 0     5        10      15       20        25 PCB??? / mm ????? ??? ????? 

Investigation of thermal characteristics of embedded resistors

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