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
* c6 |- T1 R+ ?: m0 q無法做出二極體, 只能用寄生的
vertical PNP呢???

leo911759

其實也是有的。

有一些Paper就是用Diode，或是NPN。
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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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- V) S0 u3 A( b. v( Y, j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:

- m8 l* v  d& I1 I: B* b7 C8 w( gI believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for
! G. t: z% e8 z  w, c# V& X  S: I
, B: q- j0 m; f( {6 ^- zthe "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take

on this:
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" X- x* E3 I7 F+ L" a1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current

/ x* x) n! ?- athat is probably not modeled for the "diode".

2- There usually is a specific structure for the "bipolar" that has characterization data available. When

building a bandgap structure, the good characterization is needed in order to properly determine the tempco of
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1 V+ w) o, X2 L' U! j7 n  y% `the Base-emitter voltage.

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

devices.

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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……