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？

hoodlum

小弟的看法是
會不會是標準CMOS的製程裡
2 t1 S* ^& F& F( }, j. ]7 P無法做出二極體, 只能用寄生的
, c1 b: U) |( s9 l/ A1 Dvertical PNP呢???

leo911759

其實也是有的。

( ]" P5 j- I$ k4 Z# Q$ b( i6 A有一些Paper就是用Diode，或是NPN。
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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。

, O3 M. ]/ n5 s4 F) t& e" {- s這是製程受限的關係，比較先進的製程就沒這種問題了。

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

+ |- M2 T, w" h! q( Ythe "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take

on this:
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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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( q: v7 X$ Y% o- ithat 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
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( b: z+ `" K( O' E  `' f4 l& Kthe Base-emitter voltage.
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3- The additional structure of the bipolar should help prevent current injection into other substrate tied

. a* z" M; k. z# ^devices.



There is, of course, nothing preventing the use of a P+/Nwell diode in your application.

luckyhuihui666

主要原因就是二极管不准确……