???? PCB????
??????PCB?è?????????????ê???ú?·?è???????????è?????????°????×?±??¤×÷???????ü??×????? ??????PCB?????????????è?????????¨×?????????×??????¤×÷??×??ó??PCB???????????????? ?????????°?à??????????????·?????????????×????????°??????????????×??????????°?? ?????????????¤???????ó±?????????????????????????????????????±?????±????à???????? ?????ú?ú·?????????±????±?????????????????à???????????????à???±?????????×?ú?ú???ú??????
????×????????????¨?????????????????????????????ò?????¤???è?¨?? °ü?¨×????????ú?????????¨?×????????????????????????°??????????÷???????????ì????°????????¨?? ???ó??????????????????°??????????????????????????·?????????ü?????ù???è???????????????? ????×???????????????????×????§????
?????????°????????PCB?è???????????á?¨?×???????????? ?ü??·????í?à±??ó???????¨???????????????????????????¤?×?????×???????ü?????ê???????¨?×??×÷???? ???????í?à?????¨?????????????ê?????ü??·?±????ü???÷?????ü???ê????PCB °????è?????????????????????ò?????????????????????????ü?????è???ó??×??¤???è?????±??×??????á?? ????????????????????  

1 ???????????????í
??????????????PCB°??????????ê???????????????????????? ???????????????????????????????á???ú?·???????????????±?????°?ì???ú?·???????????ù???????? ??????????????????????°??????????ù?ú?ú??????????????×???????????±??¤?ú?·????????
????????????????×??ú?·?è?????¤?????±???????÷°×?????????????????????ù?ú?ú?????ò?? ????????????????????×÷??±í????
?????¨1???????ù??????????????????????????????????????
?????¨2???????????í???????????í????×?????????±????????í???ü???????????????????????????????????¨?????????í????0.2??0.3mm,×??????í??????0.05??0.07mm,????????1.2??2.5 mm
????×????·??PCB?????í????????×é?????????·, ????????????????????(???????·???????????ù????)
?????¨3???????ó????????×÷??????,??????°???°???±?????????·????????à????×÷???????????ò??×????à??°??????????????÷??????????

2 ??×????·?????????·?????????í
???????????í?àPCB?????????????????·?¨??×??ò???????·????????????×????·?????????·?ì???????????ò?????????±???è???????ü?????????à????????????±?????????????????????
??????×????·?????????????????·?????????????????????????????????????????????????????????????·?÷????????????????????PCB???????????????á?????ù??±?????PCB???????????í??????????????????????°???????×???????????????????·??????ü???????????à??????????PCB???????????????????¨?????·????????×?????????????????????????×???????????????????????????PCB?????????????????????è???????¨??

3 ?????????????¨????????
???????à??????°??????±???????????????????????ê???????????????à?????à?????????á?ì????·????á???ú?ú???????¨???¤×÷??????±????à???????????????????????????????????????¨???????????????????×?????????????????????????????????ò??×?????±??????????ê??????

4 ?ó?????????????????????í
???????ó???????????¨???????????????÷?????????????????????????????í?è??????×??????????????????????????????????????????????ú??????????????????????×°???????????????????????????????è???ó?????????÷???????×?ì???é???????ù?????????????????¤???è????×?????×??¨???????????????????¨heat shield???×?????????¨Thermal???????ù?????????????±?ò??????·????????ú?ú?é?????????????ó?ó???????à??°????????¨?????????????í?à????

5 ????????????????×÷??
???????í?àCAD?????????????????????????????¨???????????????¨?·???????ù?????????????????????????????????ó????±??????è±??????ü???????ü???????ó?????±?????ó?????ú?à??×??ú?·???????????????ó???°?ì?????????¨?·?????§??????±????????????????????ò±?°?×°?×???¨???×?ù?????????????????è???¨?·?????????¨?????°?ì???ó???ù???????????è?????í?????????????§??????????????
????±ê×????÷?????????????à????0.1????(2.54mm),?ù?????????????ù????°????¨??0.1????(2.54 mm)?ò????0.1????????±?????????0.05??????0.025??????0.02????????

6 ?è?????ò?ì?é?¨DRC??
?????????è???ê???ó???è?????ì?é?????è????·?·????è?????ù???¨?????ò?????±???è?·???ù???¨?????ò??·?·???????°??ú?ú?¤?????è?ó????°??ì?é??????????·?????
?????¨1???????????????????????????????á?¨?×?????????????á?¨?×???á?¨?×???á?¨?×???????à????·????í????·??ú×??ú?ú???ó??
?????¨2???????????????????í????·???????????????????????·????????¨?????¨×è????????PCB????·????????????????í????·???
?????¨3???????????ü??????????·???????×????????????¤??×???????±??¤???????????°??????±??÷????·?????
?????¨4???????????·????×????·??·?????·????÷×?????????????
?????¨5???ó????PCB?????????¨????±ê??×?±ê????·??á?ì?????????·??
?????¨6???????????í??????????????????
?????¨7??????PCB????·??????¤??????×è????·?·????ú?ú?¤???????ó??×è????????·???????×?·?±ê????·??????÷???????????????°?ì??×°??????
?????¨8?????à??°??????????????????ò±?????·???????????????????????????°??????×?ì?????·??

?????? PCB????
???????è???????????????????????·?????????á???????????±???°?ì???????§?????ò?????????ù?????????í????????PCB?è????????????????
??????????·???·??????????????????????????í??????×???????????°?????×??????????ù?????????????????????÷???????????±?????ù??×??????é?????????·??????·????????????????·??????????????????±?????????×????????????????ê???ó?????????è???????°????????????·???±ê×??????í????????PCB°??????????????????í???à????????±??????ó???¨?????ü???è????????????, ???±?????????????????????ü???????????????·???????????°????????°????é?¤??
????????????
?????????ú?·????????·?????????×??????????????????????????????????????????ê?????????????ú?·??????????
??????????PCB°??????????????????ó???ù?????è?????ò???????·?????á?ò???·????
???????ì?é
????????°???????·??????¤?????????à·?????·?·???PCB???ì?¤?????ó???????¨??±ê????
????????????????????????????????????
??????????????·??è?????ò??????????????·????????ê??
?????è?????ü??????????·?·?±????ü????????°??????è±???·?·?±???
??????????????·?????????????·??????±???à????
?????÷?????÷??????·?·?±???
???????è??????????·???×°???????÷???????????÷??·??¨????
?????????÷????·???????????×?????
???????·????×ù?????ú???è????·???????
???????·????????????·????ù??????

?????? ????PCB?è??
?¨????????×??????è???ù??????????
??????×??????è???????????????????ó?????á??????×??????è??????????????100MHZ?????????·?è????×??????¤×÷???????????????ò??????50MHZ??????????????100MHZ?????°??50% ???è?????±??????????50MHz?????ü20% ???è???÷??????120MHz??
?????±?????¤×÷??50MHz?±?????ú?ú???????§???????????ê?????????????±?????±??????120MHz?±????·????????????·?è????????·??ò?ù??????·?·¨?è????PCB????·¨?¤×÷???ò???????????·?è????????????????×??????è????±??????????è?????????????¨?????????????·?è???????è?????????????????è????????????????

?¨???????????????????·
?????¨????????????×????????·???????????ò??????45MHZ~50MHZ???????¤×÷???????????????????·????????????????×????????¨??·????¨±??????±?????????????????????·??
????????????????±????????¨????±?????±??í?????????????????ì??±????????????????????¨?ò??????????±?????·?????????????·??¤???á?????ò?????¨?????¨?????????????±?ó??1/2??×??????????????????±?????ò???????à?????????????????ú?ú???????§????
??????????·??ú??????×?????±????????????????ò?????±???????????????????????????????????¨???±?????????????±??????1/2???????ò?????±??????????×?????????·?????????????????±?×??????°????????????·?????·?????????????????±?×??????ó????????????????·????????????????????¨???????????á??±?????×?????

?¨?????????????????·?¨
?????????????¨???????????§??·??ú???°?á???????????????????????±??·??ó??1/2?????????????????±???? ??°??????????????±?????????????¨???÷?????á???????????????????±????PCB?è???????????????¤?????¨?????????????????±???????í???????¤??(???±)??????????????
PCB °??????????????????±?? 0.167ns.???????????????×?à???÷???????à?????????è?????????à?????±?????ó???¨???????????÷?????????????±???ó????0.2ns??????°?????GaAs???????ò×??ó?????¤????7.62mm??
?èTr ???????????±???? Tpd ???????????????±??????Tr??4Tpd??????????°??????ò??????2Tpd??Tr??4Tpd?????????????·?¨???ò??????Tr??2Tpd?????????????????ò?????????????·?¨???ò?°???????ò????????????????????????·?·¨??

?¨??????????????????
????PCB°?????×????????§??????????????????????×è???????á??????????×è????????0.25-0.55 ohms/foot???ò??????????????????????×è×è???¨?????????????ú??×è??????????????????????PCB?????????ó??????????×???×è?????????÷×è??Zo?????????í???à????/?????ü???ò?????????é???????????????÷×è??????????????????????????????×è???????????????????????÷??????????×????????¨×????????????????????????????????ú?ú·?????????·?????????????????·???????????·???????????×???????????·?????????·ù???????????±?????????????????÷???????¨???????§??±?????????????????????????????????????????????????????????

?¨?????????????§??
?????ù???????¨?????????????????é???????????????á?????????·?è???????????§????
?????¤ ·???????Reflected signals
?????¤ ???±???±?ò?í?óDelay & Timing errors
?????¤ ?à???????????????????í?óFalse Switching
?????¤ ??????????Overshoot/Undershoot
?????¤ ????Induced Noise (or crosstalk)
?????¤ ????·???EMI radiation
5.1 ·???????
???????????ù×???????±????·???á(????????)????????×???????????????????????????±?·???????????·????¤???§???????????????§?????±?§??±???·????????±???????à???í?ó???????è???§°??????±???§??±??????????????ù???????????????????á?????è???§°????????????é??????±?×?????????EMI???????????????????????°?ì×??í?è???á???????á?ì?????????????§°???
????·????????ú?ú???÷?????ò?????¤??×???????±????????á???????????????????ò???????°×è???§????
5.2 ???±???±?ò?í?ó
???????????±???±?ò?í?ó±í????????????????????????????????????±????±±????????±??????????±??????à?????????±?????????±?ò?í?ó???÷?????????ì????
?????¨???????à?????????±?á?????????????·?è????±????·?¨×????é???????±?????±???·±??è???????·???????????±?ú?ú?????ò????????????×??????¤??
5.3 ?à???????????????????í?ó
????????????±??????????????à???????????????????????????????à?????í?ó???à???????????????????í?ó????????????????????????????????????????·??ú?????????????????ü???à???????????????????á??????????????????·????????ú?ú?????ò?????¤??×???????±????á???????????????????ò???????°×è???§????
5.4 ??????????
????????????????????×??????¤?ò??????±??????ì??·????????ò???????ó?à??????????????????±??¤??????±??¤???????±?????????????á????????????????????·??§?????????÷????
5.5 ????
????????±í?????????ù???????????????¨???±????PCB°????????à???????????????á???????à??????????????????????????
???????à?????????ü???????à???ó???ú?ú?????????????????ì?????????±???????ü???×?ú?ú???????ò??????????·?·¨??????·??ú???????????ò??±?±?????????????????
5.6 ????·???
????EMI(Electro-Magnetic Interference)?????????????ú?ú??????°ü????????????·????°??????·?????????????·?????EMI±í?????±??×??????????????±???á?????§?·??·????????¨?????????????§?·??????×??è±????????¤×÷???ü?ú?ú???÷?????ò?????·?¤×÷???????????°?????????????í?????°???????? EMI·??????í???¤??????EMI·????÷????°??ó??·?????????±????????è???????§?????????±???°?ì·????á????×??·????????????×??¨????×?·¨????????EMI???÷???è?????ò???????è?????????·???????????è???÷?·?????????ò????????????



[???ù±?apple??2004-03-15 10:46????±à??]

?¨?ù????±??????????§????·?·¨
???????????????????????ù???????°?ì??????????????·????????????????°?ì??·?·¨??
6.1 ???????????ü??????×????¤??
?????????è????????????±???±???????±???????????PCB°??????????????§????????????????±é???????????±?????????ì?????????·?????ü?????????ù???????????????????????????ù±????ò??????????CMOS?òTTL???·?????è?????¤×÷????????10MHz???????¤???????ó??7???????¤×÷??????50MHz?????¤???????ó??1.5???????????¤×÷?????????ò????75MHz?????¤??????1??????????GaAs????×??ó???????¤??????0.3??????????????????±ê×???????????????????????
6.2 ???í????×??????????á??
???????????????§?????í????·?·¨?????????·???????·?????????????á????×??????????á?????????ù?????????????ò?°?????á?????±?????????????÷???±????·?×???·??§?¤??±?????????·??ò±????ì??±???????????±??????÷??×???????·??§×????ù?¤?ú???¨???é??????PCB×????????????ù±??????á?????????¨??(Daisy Chain)??????????(Star)·?????
???????????¨???????????????????????????????????÷??????????????????????×è????±?????????????????×è????????????????????????????×????????????¨????·????????¨??×????§??×???????????×???·??????¨??×??????????×100%???¨???????è?????????????????¨????????·??§?¤????????????°??????¤????????????Stub Delay <= Trt *0.1.
??????????????TTL???·????·??§???¤????????1.5???????????????á????????????????????????????????×è???????á??????????×????á??????????????????????????????????????????????
?????????????á?????????§??±????±??????????????????????????????????PCB°??????¤?ê????????·??§????????×????????÷???ê????????????×?????·?·¨??????·??§?????è????????×è????????×è??×è???????????????÷×è???à???????????¨?????¤???????????¨??CAD?¤???????????÷×è????????????????×è??????
??????????????????×??????????ò??????????×è???????????????????ü????????????????????????????RC??????????RC???????????????????????????????????????????¤×÷±??????¨???é????????·???×??????????±???????????????????í?????±????RC?????????????????????°?ì????????×?????????????
??????????×è???????????á?ú?ú???????????????????á????????????????????·????????±???????°?ì???ó??×??????????·??
??????????×è????????????????????????????°????÷????????????????????????
????×??ó????·?????·?????????????????·????????????è??·??????????????ü?????????????á????????????????????????±??????ù????????????TTL????????(ACT, HCT, FAST)??
????????????????????×è??·?×°??????°?×°??????±??????????¨??SMD±í???ù×°??×è±??¨?×?????????????????????ù??SMD·?×°?????????×???????????????¨?±????×è????????°?×°·????????????±·?????????·?????
???????±°?×°·???????×è??????°?×°????????????????????×è?????·°???????×è??????×è???????ü?????×??·????????????????¤?????±°?×°?á??????×è????????????°?×°·????ò°?×°???????ü????????????????????×è?á????????????×??????é??????×è???????·???ì??PCB×??????á?????§?§???????±?????§°??ò????
6.3 ??????????????·?·¨
???????????????????ê??????????????PCB°?????????????(EMC)??????·???????????±??¤PCB°????????????????????????è????????????????????????????????·????§??·?·¨?????????????·°???×???????????????×???????????????·???????·?·¨??????·?·¨??????"±í??????"????"Build-up"?è????×?PCB????????±í???????¨???????¨?¤?? PCB ??????±??????????????á?????????????×??×é???????? ????×è????????????±í??????????????????×????????á?????ü??±????ò???????? PCB????????PCB ????????????×??????????á???????ó???°?ì????????×??????????÷???·????????·??§×????¤??????????·????ü????±??????÷???·???????????±?????????÷????×???????????·?×°?÷??????±????????????????????¤???????????????÷???·???????á????????????????
6.4 ???ü??????????
?????????????????·???????????????????±???????????????????·?????í?????????????????????§???????????????????°?ì????????????°??????????·?·??·?????
?????±?????????±???????????????·?????????????????????????????????±???????????????§??×????????????????????????÷????×ù???????????????????????÷?????ó?????????à?÷?????à????×?????????
???????????????????????÷????????·??????????????????????????±??????
?????????????????????????¤???????????á???????????·???????·?·??????·????????×???????·??
????×??????????????????????????ò???ü×??????·?·???é?????????·???????·?·???????????????ü×????ò????±??·???????é?????á?????ì???§??(???ì?????·???ì??)???ì???????ú?úEMI·????????±×??í???????????·??±??·??????±????????????????ò???ü?ú?ú??·?????±??·?????ü??????±???

?á????
???????????·?è????????·??????????è????????ZUKEN?????????????·??????·¨(Route Editor)??EMC/EMI·????í??(INCASES,Hot-Stage)??????·?????·?????????±????ù??????·?·¨????ר?????????????????????·?è?????????????????????????????·?è???±???à???ò???è?????????????????ò?????±???à?????????????÷???????±???????ü???????????????±?????????ú?ú???????????????§?????ò?????è???????è?¨???÷?ò????×??????????????????????ú×??è?????ó?????????è??????????????PCB?è???????????????????è??????????????????????????????????????????????????????