標題: 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？ [打印本頁] 作者: scy8080 時間: 2012-2-3 02:59 PM 標題: 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？ 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？作者: hoodlum 時間: 2012-2-3 10:59 PM
小弟的看法是% C, v; |4 P5 r( b C
會不會是標準CMOS的製程裡! E% f8 a. E( J6 j; Q
無法做出二極體, 只能用寄生的 0 H- N4 ?( R$ ~2 D$ f: ?: Qvertical PNP呢???作者: leo911759 時間: 2012-2-8 04:02 PM
其實也是有的。: V' x o$ d- |. U& ^
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有一些Paper就是用Diode，或是NPN。% U; c9 p- ~, |2 S$ R% B
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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。 - b! t; V' o) W2 G: y% u' w+ `' W" Y- X* c
其中的寄生等效Diode會有Latch-up的問題。 & B* ~# s0 L8 z3 i7 r# S# |+ A
這是製程受限的關係，比較先進的製程就沒這種問題了。作者: patrick02046 時間: 2012-2-9 01:24 PM
在EDA Board 抓的資訊， 參考一下:7 r$ v! Z* t1 V+ m
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I believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for / I, V# {5 s) C* O2 X+ y5 `
7 f! B6 j) L- ?8 _the "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take ; H3 }$ L8 k) R m7 O
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on this: 9 @6 h, L+ c# `0 B. a * l/ J4 Z. c6 t1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current 9 e7 h9 v- t4 E% N+ U* q* a7 l+ K
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that is probably not modeled for the "diode".: K5 l9 [) X2 x, _! I0 C
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2- There usually is a specific structure for the "bipolar" that has characterization data available. When / O! R7 P0 E; W+ l. W4 C7 d8 D# o2 y; R6 J0 b+ [
building a bandgap structure, the good characterization is needed in order to properly determine the tempco of 1 r7 `. s6 g6 N. \
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the Base-emitter voltage.# W+ E- A2 a. n7 b9 J) n* I) h
; O* ~$ [4 A. T( Q2 W1 T) l$ i3- The additional structure of the bipolar should help prevent current injection into other substrate tied - Z. k4 X- m! y7 n$ s1 U2 m" ^ ' z" H$ o) R, x! P# I( W) ?devices. / Q) L" w; ~ d$ r- j7 N" v7 J ?/ l8 z6 C$ H ; Y, H5 w( U0 g' ]- A 1 k; y# R, K( _There is, of course, nothing preventing the use of a P+/Nwell diode in your application.作者: luckyhuihui666 時間: 2012-4-13 08:06 PM
主要原因就是二极管不准确……