9 z, t- G. B; y: R: [- I/ C) A這是製程受限的關係，比較先進的製程就沒這種問題了。作者: patrick02046 時間: 2012-2-9 01:24 PM
在EDA Board 抓的資訊， 參考一下: & c" K& \# ^; j2 J/ v; R : p: f* m4 `: a) nI believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for " N. C8 K- {3 R
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the "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take ' O% `6 ?, M* [- [( \0 Y [! _) v f* J' s1 v; Gon this: 5 m" D1 e' H& ]4 s3 Z) b: _ 5 `; L2 z& [2 y6 w1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current 5 F- v4 T! X3 g: \8 m; ^
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that is probably not modeled for the "diode". , u# S$ ?; @& _5 S/ k5 f! ~$ j: [0 c( B
2- There usually is a specific structure for the "bipolar" that has characterization data available. When ! Y c5 t9 L4 N( ?
# S+ `; ]2 x5 Obuilding a bandgap structure, the good characterization is needed in order to properly determine the tempco of 0 V0 S# P' {- B% N- y7 L3 M% N) _# Y7 B
the Base-emitter voltage. " C+ r W0 P7 o9 w H: R5 _3 T! C# Z6 z! E# u
3- The additional structure of the bipolar should help prevent current injection into other substrate tied 0 ]3 @. p; E5 h2 z , t$ S' x2 K. x$ ^devices.2 z5 }1 T- p9 r
8 n5 `$ k+ j+ N 8 F, M, k+ P* U# L1 M 9 T9 ?- q' G9 f* AThere is, of course, nothing preventing the use of a P+/Nwell diode in your application.作者: luckyhuihui666 時間: 2012-4-13 08:06 PM
主要原因就是二极管不准确……