CMOS工艺下bandgap 负温度系数器件，为什么使用PNP管而不是用二极管？

scy8080

CMOS工艺下bandgap 负温度系数器件，为什么使用PNP管而不是用二极管？

luckyhuihui666

主要原因就是二极管不准确……

patrick02046

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

the "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take

on this:

; ~3 t% ?# T/ p1- 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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2- There usually is a specific structure for the "bipolar" that has characterization data available. When

building a bandgap structure, the good characterization is needed in order to properly determine the tempco of

the Base-emitter voltage.
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' M3 }( W6 N8 `; {, |! ^3- The additional structure of the bipolar should help prevent current injection into other substrate tied

devices.
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; K7 A& ^/ |; [9 o( X' ~There is, of course, nothing preventing the use of a P+/Nwell diode in your application.

leo911759

其實也是有的。

* ?& q0 A+ z& d3 E, M. m; x有一些Paper就是用Diode，或是NPN。
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7 t+ ?" F4 \, S: g! a9 O: [而會用PNP 是因為早期CMOS製程中，只能寄生等效PNP電路。

其中的寄生等效Diode會有Latch-up的問題。
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6 V4 G7 s4 _) Y這是製程受限的關係，比較先進的製程就沒這種問題了。

hoodlum

小弟的看法是
會不會是標準CMOS的製程裡
無法做出二極體, 只能用寄生的
  [8 P- j$ h9 G6 i1 `- R) pvertical PNP呢???