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
/ t( p/ @: \6 m" Vvertical PNP呢???

leo911759

其實也是有的。

' j0 Q1 o* p( p6 A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。
8 L9 R0 N% N% W5 a1 j5 V3 `! Y' {
% \5 c4 w: d1 i; b" z! I1 Q+ v其中的寄生等效Diode會有Latch-up的問題。
; \8 R2 F; D/ b/ M, {
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:

2 \! H  P( g! |1 t* @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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* I& a9 X) k7 [, [0 _, Z: v1 Nthe "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take

on this:

; k5 H$ a5 x4 g: {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".

) B% k' M$ W1 H5 A2- There usually is a specific structure for the "bipolar" that has characterization data available. When
$ U9 z5 s1 q. t2 b: p
building a bandgap structure, the good characterization is needed in order to properly determine the tempco of
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8 q" H( v  s: h5 j) w: gthe Base-emitter voltage.
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" A% o9 _1 T# R' M  A0 c3- The additional structure of the bipolar should help prevent current injection into other substrate tied

: O2 A9 ~8 j) F' ^# d7 edevices.

! b8 M* `( [" _9 [# S

4 _. T* q! A+ X3 r/ u( p+ ZThere 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……