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
, z4 h9 T8 t0 j- r會不會是標準CMOS的製程裡
2 t% x# k! n: ?無法做出二極體, 只能用寄生的
7 y3 L) L: x: e4 r, b, Qvertical PNP呢???

leo911759

其實也是有的。

- w( o- s1 u; g& i# T: L( ?5 c. T4 K' q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。
, V' y4 L# V2 I1 p/ k
: G& P& M& \4 Y$ e2 a8 p其中的寄生等效Diode會有Latch-up的問題。

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:
0 r$ B! i/ `6 ?# f$ i) Z0 x
I believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for

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:

3 |* Q2 _" q% a( D* N1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current

that is probably not modeled for the "diode".

2- There usually is a specific structure for the "bipolar" that has characterization data available. When
+ V( U! `6 w& A1 V2 |" t  g" @
building a bandgap structure, the good characterization is needed in order to properly determine the tempco of
( W' _1 o& A+ [  ~) `: u
5 b  t1 n' p7 V3 Ithe Base-emitter voltage.

3- The additional structure of the bipolar should help prevent current injection into other substrate tied
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/ w* f) {& B8 w$ c$ Wdevices.
9 p( B  C/ |+ P; V

# e2 |' u7 R$ y% V  Q; X, e2 ?
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……