(1) +跨
  һ˫ܻ MOSFET,C/Dһ赽Դ,ƽ,ƽ¾Դƽ

(2) OC/OD +跨
   1) ơպΪ OC/OD ĳϡ

(3) 74xHCTϵоƬѹ (3.3V5V)
   5V TTL ƽݵ 5V CMOS  3.3V5V ƽת
   3.3V CMOS ĵƽպú5V TTLƽݣɺϣ, CMOS ƽǽӽԴƽġ
  ۵ѡ 74xHCT(HCT/AHCT/VHCT/AHCT1G/VHCT1G/...) ϵ (Ǹĸ T ͱʾ TTL )

(4) 뽵ѹ (5V3.3V, 3.3V1.8V, ...)
  ƽԴ߼,͵ƽ
  ""ָԴ,ϹϵѹԴ,ԽԽȡ (ı뼶·)
  ,74AHC/VHC ϵоƬ, datasheets ȷע"ѹΧΪ0~5.5V", 3.3V ,Ϳʵ 5V3.3V ƽת  

(5) רõƽתоƬ
  ľ 164245,ѹ/ѹ,ߵԴͬͨõĵƽת,ҲǺܰ (ǰǣ45/Ƭ,,Ҳ),ǱҪ,ǰ

(6) ѹ
  򵥵Ľ͵ƽķ5Vƽ,1.6k+3.3kѹ,3.3V

(7) 跨
  ̫,ʱֻһ衣ĳЩоƬȻԭϲƽԴ,ֻҪһ,֤뱣( 74HC ϵΪ 20mA),Ȼǰȫġ

(8) Ϊ޲Ϊ
  ֻҪ˵ƽݵĹɡĳЩ,ͲҪرת,·õĳ 5V ߼, 3.3V ƽ,ֻҪѡʱѡΪ TTL ݵ,ͲҪκת,൱˷3)

(9) Ƚ
  Ǵ,,ʲô˷ŷ̫ˡ

2. ƽת"Ҫ"

(1) ƽ
  ƽת,ľҪ߼ӿڵĵƽ⡣ƽԭ
  VOH > VIH
  VOL < VIL
  ټ򵥲ˣȻ,ǿ,һޣ
  |VOH-VIH| > VN+
  |VOL-VIL| > VN-
  ,VN+VN-ʾޡ
  ֻҪԭ,Ϥ,ԺȻҵ,ǰķ(3)(4)ȷԵӡ

(2) Դ
  Դϵͳע⡣ĳЩƽԴ,ûеԴʱͼ,ܿоƬֳõİ취ܾǷ(5)164245ٶ,(1)(7)ҲԿǡ

(3) ٶ/Ƶ
  ĳЩתʽӰ칤ٶ,Աע⡣񷽰(1)(2)(6)(7),ڵĴ,ͨصݳ,ȻӰźٶȡΪٶ,ͱС,ֻɹֳϷ(3)(4)ǱȽġ

(4) 
  Ҫһĵ,(1)(2)(6)(7)Ͷˡһһʵһµ,ΪٶĹؼǶԸصݵĳ 