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
vertical PNP呢???

leo911759

其實也是有的。
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有一些Paper就是用Diode，或是NPN。

4 N9 O6 s( y2 U/ a: N! s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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0 S/ ?8 _) W) [/ V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:

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:

# x/ C4 H' `2 I0 a  z1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current

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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building a bandgap structure, the good characterization is needed in order to properly determine the tempco of

the Base-emitter voltage.
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3- The additional structure of the bipolar should help prevent current injection into other substrate tied
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4 E2 E  @0 @) D+ n( }devices.
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7 [( T2 _0 a7 x, \* Y: `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……