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
! `* }% t5 d) ^會不會是標準CMOS的製程裡
無法做出二極體, 只能用寄生的
" G! `1 T0 u  L3 Q1 `) qvertical PNP呢???

leo911759

其實也是有的。
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/ {9 q* [% n$ i" J0 v7 y: i" P有一些Paper就是用Diode，或是NPN。
! {( t0 i) N8 w
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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其中的寄生等效Diode會有Latch-up的問題。

# O+ o' V6 Q; a2 ~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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; W) ]' v; N" t( \I believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for

% S2 Q, M. ?1 i; l( K% t% U4 xthe "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take

on this:

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".
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2- There usually is a specific structure for the "bipolar" that has characterization data available. When
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. @" g) z! g9 g$ ~) ~3 [building a bandgap structure, the good characterization is needed in order to properly determine the tempco of

0 J2 S% t! P/ t2 \5 z; i2 O+ H  athe Base-emitter voltage.

" e" l) s; Y( }, p0 h. j  g( G9 B3- The additional structure of the bipolar should help prevent current injection into other substrate tied

: @: e1 v  R( c1 ]5 o8 u5 c" E# @" e- }devices.



, |; v4 \* u1 [7 x6 B, q' bThere 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……