BGA??PCB????????×é?????¨??CPU??NORTH BRIDGE??SOUTH BRIDGE??AGP CHIP??CARD BUS CHIP???????ó?à????bga??????°ü×°???ò??????80?????????????°???????????á?????à????package?????????ò???????????íBGA package??×????????????????á?????ó???°?ì??
?¨???·????BGA???ü????????????????????????????·??????à??
1. by pass??
2. clock????RC???·??
3. damping?¨????????×è????×é??????????????memory BUS??????
4. EMI RC???·?¨??dampin??C??pull height??????????????USB????????
5. ???ü???????·?¨????????CHIP?ù???????????·??????CPU?????????·????
6. 40mil?????????????·×é?¨??C??L??R???????????????????·????????AGP CHIP or??AGP??????CHIP???ü??????R??L·???????????????×é????
7. pull low R??C??
8. ??°??????·×é?¨??R??C??Q??U??????????????×??????ó????
9. pull height R??RP??
1-6???????·?¨????placement?????????á???????????üBGA?????è????±????í??????7?????·???????????????????á????±??????üBGA??8??9??????°????????·????????????????????????
?à????????BGA???ü??????????????????????????????ROUTING?????è?ó??????
1.by pass =>??CHIP???????±???±????CHIP pin????by pass??????by pass?????òvia??plane????CHIP???????±??????BGA??VCC??GND pin???í??????via?????¤????????100mil??
2.clock????RC???·=>?????í?????à?????¤?ò°üGND???è?ó??×???????????????????????????VCC·???????
3.damping=>?????í?????à?????¤?°·?×é×??????è?ó??×???????????????????×é??×é×????????????????ü??????
4.EMI RC???·=>?????í?????à??????×?????°üGND???è?ó???????§???ó?ê????
5.???ü???????·=>?????í??°üGND?ò×??????????è?ó???????§???ó?ê????
6.40mil?????????????·×é=>?????í???è?ó????????±í?????ê???????????????ê??±???????????????????????±?????????????BGA?????????????ì????±???????????
7.pull low R??C=>?????????ó??×?????????
8.??°??????·×é=>?????????ó??×?????????
9.pull height R??RP=> ?????????ó??×?????????
?????ü?????????÷BGA????×????????í??????????????±ê???÷??????
A. ??BGA??????????×???·???VIA·?±???×ó????×ó??????????????·??ò?ò????×????ò×????è??×????????÷????
B. clock?????????í?????à???ó???±??R??C???·??CHIP???????±????????????·??????í??
C. USB??????R??C???????ê??????×?????
D. by pass??????CHIP pin????by pass??????plane????·¨??????by pass?????ü??plane??
E. BGA×é?????????????????ù????????±??????è?¨???í?????à??VIA?????????????°3MM placement?????????÷??×??????ò??????×??????????????ó???ò???????¤????×????????????ù?????òVIA?ò??PIN??PIN?????????í????BGA??????????????????±í??????????????????????VIA????
F. BGA×é????????????????·????????ò????????±???????????×???
