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
+ y0 j; @0 \2 G; o* Gvertical PNP呢???

leo911759

其實也是有的。

  R1 K5 |  n# m: {) D, o有一些Paper就是用Diode，或是NPN。

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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- x6 d! ]/ s+ K' W! f其中的寄生等效Diode會有Latch-up的問題。

% ^5 D  w4 q) P. f* |3 G' ~# E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

" R+ q* Q+ @! Vthe "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

% Y+ n3 N4 J3 Z+ ]" \& cthat 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
" U( R) I4 M( {# S7 s4 E/ ]5 d
building a bandgap structure, the good characterization is needed in order to properly determine the tempco of

1 y: ^# q5 s5 O: O8 R+ sthe Base-emitter voltage.
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3- The additional structure of the bipolar should help prevent current injection into other substrate tied

devices.

1 [3 K  J! j! p  W. k" B" K

4 T  X8 n9 X+ GThere 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……