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在EDA Board 抓的資訊, 參考一下:
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7 i1 k2 Z3 ? A7 MI believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for
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! G2 ?5 N2 [# [) {# T. V2 e/ K$ ~the "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take
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1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current
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that is probably not modeled for the "diode".
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7 F Y- O: U+ P2- There usually is a specific structure for the "bipolar" that has characterization data available. When & X9 ]$ h' ~; j6 O/ e
) a! u# b: J, D4 P% {* w+ m/ Y8 mbuilding a bandgap structure, the good characterization is needed in order to properly determine the tempco of
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the Base-emitter voltage./ c7 o$ O5 K5 [) w: W
" X' G c" N U% z; w8 U3- The additional structure of the bipolar should help prevent current injection into other substrate tied 3 h4 S$ j: u# U3 Z e1 J. u1 w0 Z
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devices.
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4 l1 b) ]1 \4 W7 d& RThere is, of course, nothing preventing the use of a P+/Nwell diode in your application. |
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