标题: ????ddr sdram ???¤?? [打印本页]

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作者: dancruiser    时间: 2006-6-26 08:39     标题: ????ddr sdram ???¤??

??DDR SDRAM ???????±????·????ó???ù?????????????¤????????date??addr??control??clock?????÷×é?????????????¤??????????????±????¤??
??????

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作者: zing    时间: 2006-6-26 11:36

??????data/addr/clock?è?????¤????control??????????·???????????????????·????ó???????è?¨??data/addr/clock ?ó??10mil,control??50mil,?????÷??PCB×????¤???????ù??×è????????????????????·??????????????ù????????????????????????

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作者: dancruiser    时间: 2006-6-26 14:12

???????ó???????????????????÷??
????100M??????????????TX+??TX-???¤???????ó??°??è?¨???à????
????data/addr/clock?????????¤???°????±??è?????ó?????????????????????????¨±?????4??°??????±?ò????????????????????????×??????????????¨±?????????66pin??ddr sdram)???¤????
?í???????¤??????????????????????×è??sdram??????????cpu????????×è?????????¨?ò????????????????

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作者: zing    时间: 2006-6-27 11:49

100M????????????,TX+??TX-???¤??????°????????????????ù±???×?????·?×??????ò???ù±??????????????????????¨???è???????????°????????5mm?????????????ó????
???????¤?????????????è??×????????é????????????????????°ì·¨
???¤???????????¨?·?????????????????????????????????????????¨?·??????????±??????×?í???????????????????ò??±í???è?????????í???????á?ü?????×?í???????????ò???ù????

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作者: wards    时间: 2006-7-7 00:08

?¨?é??????DDR layout guide??Ethernet PHY layout guide.
???????é,
DDR in PC:  Clock length match should be +/-10mil per pair impendance is 100ohm;
           Data: +/-50mil,  60ohm;
          Addr/Control: +/-1inch, 50ohm;  
...
So you also need control the trace's width,space and PCB stackup

LAN: TX+ and TX- should be +/-100mil in 100M. and +/-30mil(at least 50mil) in 1000M.

???¤????????????net???¤??(??CPU????????????DDR????),????????????×è???°,??????????×è,????????????×è?ù??????????IC???à?????ù.

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