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
無法做出二極體, 只能用寄生的
vertical PNP呢???

leo911759

其實也是有的。
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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。
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其中的寄生等效Diode會有Latch-up的問題。

" d6 @  X3 u1 L8 o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
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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

on this:
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1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current

) H; Y, X' A% p$ h# b. [/ jthat 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

& V+ n* M- }2 Ybuilding a bandgap structure, the good characterization is needed in order to properly determine the tempco of
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the Base-emitter voltage.

8 Z% t! ]$ U. i' E9 A$ y3- The additional structure of the bipolar should help prevent current injection into other substrate tied

devices.
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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……