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
5 O+ J- W/ S6 h會不會是標準CMOS的製程裡
% n- E3 ^/ o- I' S' [無法做出二極體, 只能用寄生的
$ O: j" Z1 ^0 o/ S3 s; `vertical PNP呢???

leo911759

其實也是有的。

* h# A$ D" D9 |, A: L/ @有一些Paper就是用Diode，或是NPN。
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7 ~) v( H3 x: C$ j' Z( S而會用PNP 是因為早期CMOS製程中，只能寄生等效PNP電路。

, @! X0 O/ f6 G% p. _, O% q其中的寄生等效Diode會有Latch-up的問題。

/ t+ M: m- y5 [/ A2 @& I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:

I believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for
+ Q7 @- Z* j% s
the "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take
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on this:

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

that is probably not modeled for the "diode".
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4 v' E: z7 h3 c2- 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

: }; }& ^( C2 h# W% d/ |/ Jthe Base-emitter voltage.

3- The additional structure of the bipolar should help prevent current injection into other substrate tied
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devices.



4 j! p+ w" O1 C  m" KThere 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……