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？

luckyhuihui666

主要原因就是二极管不准确……

patrick02046

在EDA Board 抓的資訊， 參考一下:
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* Q  o& f/ \2 MI believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for

7 A$ a4 u' s6 t! K: B" tthe "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take
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) H8 m- h8 e, X. i% f1 I  Bon this:

1- 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
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  h) Q8 j1 n, Hbuilding a bandgap structure, the good characterization is needed in order to properly determine the tempco of
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the Base-emitter voltage.

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

6 a5 U9 Y6 ^9 m. I: v  K" \, {. l9 ~devices.

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- i! |4 Q- Q/ Z2 A' Q! ZThere is, of course, nothing preventing the use of a P+/Nwell diode in your application.

leo911759

其實也是有的。
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9 V9 n$ q5 n. ?" \7 t0 w" h. i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。

! i7 P0 A9 k, p; Z8 g, {" [其中的寄生等效Diode會有Latch-up的問題。
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這是製程受限的關係，比較先進的製程就沒這種問題了。

hoodlum

小弟的看法是
  D9 ~1 t& i7 _; _會不會是標準CMOS的製程裡
無法做出二極體, 只能用寄生的
7 i% X( A0 H' f% ~vertical PNP呢???