|
|
在EDA Board 抓的資訊， 參考一下:
: Z( n& B; w# L1 Y- g; B i5 n. P |. X m1 }. ^( n; n
I believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for
$ g2 l* h6 p& Q+ A& f4 |
0 {/ m2 y% R4 K& R. R/ P* \the "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take 1 m! K0 K5 r6 Y/ N3 d( m& K5 [* g
) |) a5 n9 a3 Z: ?- m a. ~: j6 yon this:4 U% H$ l% d/ q5 i3 s) [3 y
q$ [8 P+ E3 I
1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current 7 e" c/ q) p8 t
2 \$ y- G' s G- A6 P G# s6 ?: B0 f
that is probably not modeled for the "diode".: V/ e5 J% u$ p/ @
$ U& X M4 e& M: J0 W9 w& [8 b; i
2- There usually is a specific structure for the "bipolar" that has characterization data available. When
: @& ^4 t; s1 y9 h- |* K" L4 Q7 y3 K% W0 N: t( {& M7 z0 c0 L
building a bandgap structure, the good characterization is needed in order to properly determine the tempco of
5 j# B- i* w7 J' Q S
3 `! U+ [/ }7 n* H3 C2 Lthe Base-emitter voltage.5 G4 j! {* `) o) T
9 C( D) ^1 i+ ?$ D$ ?
3- The additional structure of the bipolar should help prevent current injection into other substrate tied 5 G& J- L# @2 q! s
o `8 L# O9 Q) Odevices. h9 ~; _ l5 y( w% s6 c
" s. ^2 P! m. Z* v9 q
& h" P1 ?# L1 D: `: K6 F L* Y% H; M! S3 ^3 o" A
There is, of course, nothing preventing the use of a P+/Nwell diode in your application. |
|
[複製鏈接]
IP卡
狗仔卡
發表於 2012-2-9 13:24:53
顯身卡