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:

6 Q3 R0 B" U2 c8 c* U! B1 Y3 h' gI believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for
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2 s" f( [  l: `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:

1 u7 M# \7 s$ F7 L4 N' ?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".
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# g. `5 k$ g" j/ {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
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* P/ F; j/ i, C2 _the Base-emitter voltage.

) i0 i) l% d! Z4 M" V5 `- `9 ~3- The additional structure of the bipolar should help prevent current injection into other substrate tied

1 [6 o5 h# j4 ~; \+ ydevices.

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There is, of course, nothing preventing the use of a P+/Nwell diode in your application.

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。

其中的寄生等效Diode會有Latch-up的問題。

0 O% v  e* a& J$ e4 N4 ^% w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
7 Q4 L! D# O. a9 A. W2 [& T6 t會不會是標準CMOS的製程裡
# F, C  T: ?- N. d* A無法做出二極體, 只能用寄生的
# D7 r9 Q* n* i, D  v" l9 }0 L/ Nvertical PNP呢???