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
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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

8 G$ u  t% c" W/ M6 e7 o& l& }on this:
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1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current

, M8 T% [0 A2 R, \: Othat 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
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building a bandgap structure, the good characterization is needed in order to properly determine the tempco of
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the Base-emitter voltage.
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' C; o. w4 t! u# P$ j3- The additional structure of the bipolar should help prevent current injection into other substrate tied
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devices.
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There is, of course, nothing preventing the use of a P+/Nwell diode in your application.

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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7 k+ S1 T# j/ _, p; ]3 i6 H# i  u0 G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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$ a8 z! |" O' }$ o2 l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
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無法做出二極體, 只能用寄生的
vertical PNP呢???