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作者: wards 时间: 2004-7-3 11:58 标题: ??????????????????????×???(?ò??×??á)

1. ??????????×???·?°?

(1) ?§????+??????×è·¨
   ?????????????????????ò MOSFET??C/D??????????????×è?????????????????????é?????????????ó??????????????????

(2) OC/OD ?÷??+??????×è·¨
   ?ú 1) ?à???????????÷???????????? OC/OD ????????

(3) 74xHCT???????????? (3.3V?ú5V)
   ·????????? 5V TTL ?????????? 5V CMOS ?÷??????????×÷ 3.3V?ú5V ????×?????
   ???????????? 3.3V CMOS ????????????5V TTL?????????¨?????????? CMOS ??????????×??????ü????????????
   ???????????? 74xHCT(HCT/AHCT/VHCT/AHCT1G/VHCT1G/...) ???? (????×??? T ??±í?? TTL ????)??

(4) ????????????·¨ (5V?ú3.3V, 3.3V?ú1.8V, ...)
   ·??????í???????????????????????÷????????????×÷??????????
   ???????°?????±???????????????í?à?????????÷?????????í???????????????????????????à?????÷???????????????? (??±?????????±??¤???·)??
   ??????74AHC/VHC ???????????? datasheets ?÷?·×??÷?°????????·??§??0~5.5V?±?????????? 3.3V ???????????????? 5V?ú3.3V ????×?????

(5) ×¨??????×???????
   ×??????????? 164245????????????×÷????/?????????????í??±?????????????????×??¨????????×???·?°?????????????°??ó?? (°??°?????ò?????¤45/?????????????????ó??????)???ò????·?±?????×??????°????·?°???

(6) ??×è·???·¨
   ×??ò??????????????·?·¨??5V????????1.6k+3.3k??×è·?????????3.3V??

(7) ???÷??×è·¨
   ??????????????????×è???à?????±???????????????????÷??×è?????????????????ò???????í???????????????????????????????????÷??×è??±??¤????±??¤???÷??????????(?? 74HC ?????? 20mA)????????°???????

(8) ????????????·¨
   ?????????????????????????????????????ù±??????è????±???×??????????????·???????????? 5V ?????÷???????????? 3.3V ?????????????????÷???±?????????? TTL ?????????????è??????×????????à?±????????????·?·¨3)??

(9) ±????÷·¨
   ???????????????á????????????????????????·?·¨????????????

2. ????×??????°???????±

(1) ????????
   ????????×?????????×??ù±??????????????????÷???????????????????????????????????ò????????
   VOH > VIH
   VOL < VIL
   ???ò???????????±??????????????????????±????????¨?????ù??????
   ??VOH-VIH?? > VN+
   ??VOL-VIL?? > VN-
   ??????VN+??VN-±í?????????ù??????
   ???????????????ò???ì?¤?÷?à?÷????????????????????????×????????????í·?°??????°????·?°?(3)(4)???????·?????÷??????????????×???

(2) ???????ò
   ?à????????±???×????????????????÷???????í???????????????????????????????±????????????????????????????????????????×?????°ì·¨????????·?°?(5)????164245?????????????í??·?°?(1)(7)????????????

(3) ????/????
   ????×???·????°?ì?¤×÷???????ù??±???×???????·?°?(1)(2)(6)(7)????????×è?????????¨????×è????????????????±????á?°?ì???????????????????á??????????±?????????×è???????á?ì????????????????????·?°?(3)(4)??±????í??????

(4) ????????????
   ?????è?????¨?????÷??????????·?°?(1)(2)(6)(7)?????????????????????ú?????????????????????ò???????????????ü??????????????????????????

(5) ?·??
   ????·?°????÷?????à???ò????????·?±????·???à??????????????????×??????·????????×???????????????·?°?(3)(4)??????×????????÷????(245,541,16245...)???ò????·?°?(5)??
   ????????????????????×?????????16245??????à???????74AHC04???à??SO-14?????????????ó???????????????? TI ?ò Onsemi ????/???????????????? 74AHC1G04, 74AHCT1G04...????????°?????????????????

(6) ??±?&????
   ?°??????164245?????????????????°???????±?°????6?????ò??????·??????ò???????????ù±?????????????????????
?à??°??¨?ù????????×???

作者: zona 时间: 2004-7-5 11:49

???????? OC/OD ?÷??+??????×è·¨??????????????????

作者: wards 时间: 2004-7-6 17:20

??°???????pin??×???OC/OD??????... ?????é?????????ú??????????

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