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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0 s1 e1 m# _/ ^4 D有一些Paper就是用Diode，或是NPN。

& n9 \* U) J/ M  p) [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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+ K) J2 Q4 z; ^/ F! D3 b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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: h8 @2 o& W" d" z0 M! I3 WI 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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+ e' F- ?0 M. ?9 u7 Dthe "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take

on this:

. o% H4 J7 l6 ]: T+ _1- 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".

$ V3 U* J% z6 {, x6 f' |+ C2- There usually is a specific structure for the "bipolar" that has characterization data available. When
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/ P7 ?3 o/ H3 w8 Nbuilding a bandgap structure, the good characterization is needed in order to properly determine the tempco of

' y7 _3 M7 w+ }; r: b! vthe Base-emitter voltage.
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3- The additional structure of the bipolar should help prevent current injection into other substrate tied

7 s6 F) D* }  l1 ?& cdevices.

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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……