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在EDA Board 抓的資訊， 參考一下:
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I believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for 0 n8 t3 h4 U! @7 ]5 x' y' j2 g
# C. |# O1 B& {. h* u, Mthe "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take 9 v4 U) {4 E3 {! C( U
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on this:
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* O! z7 R2 Q" U1 l1- 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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6 i( R: O" a9 {) w2- There usually is a specific structure for the "bipolar" that has characterization data available. When 8 U; R9 [$ |% d+ V2 f* t: n
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building a bandgap structure, the good characterization is needed in order to properly determine the tempco of 3 L7 k6 I- N6 Q: P; j, d
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the Base-emitter voltage.
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3- The additional structure of the bipolar should help prevent current injection into other substrate tied . E8 V* J+ F3 C; Y/ e0 h
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devices.: ?$ _2 `$ G6 X$ K
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There is, of course, nothing preventing the use of a P+/Nwell diode in your application. |
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發表於 2012-2-9 13:24:53
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