有關hspice inverter chain design

ShengKuanLa@FB

不好意思，大學修積體電路導論，目前的作業出到inverter chain 但卡在這好久，麻煩前輩們解惑了!問題是4階inverter chain，條件給了minimum size還有基本的cl 1pf等等，我用了網路建議的f=3.8試看看，第一關跑圖就失敗了。。。tr0跑出來的圖形歪七扭八整片顏色。。。下面是我的gedit inv.sp

* `/ p2 x1 M& w) m( _/ l6 e
*****circuit****
5 g( W  L6 P7 O" `, q3 u.subckt sub1 in out vdd vss
% a# m0 |( {" G1 p8 V1 M/ LMp1 out in vdd vdd P_18 w=3u l=0.18u m=1
4 m/ R& ?* `$ v  JMn1 out in vss vss N_18 w=1u l=0.18u m=1
.ends sub1
/ S# V* t* f4 C/ p/ b
  J8 f$ E4 D/ {.subckt sub2 in out vdd vss
Mp2 out in vdd vdd P_18 w=11.4u l=0.18 m=2
( b% X7 Y8 j! d! `7 \Mn2 out in vss vss N_18 w=3.8u l=0.18u m=2
.ends sub2

.subckt sub3 in out vdd vss
$ ]  c& S1 M* U1 f" Q! N# VMp3 out in vdd vdd P_18 w=43.32u l=0.18u m=3
Mn3 out in vss vss N_18 w=14.44u l=0.18u m=3
+ d5 q5 [1 O" Y6 o( }.ends sub3

.subckt sub4 in out vdd vss
Mp4 out in vdd vdd P_18 w=164.6u l=0.18u m=4
" t, h6 ~6 z2 MMn4 out in vss vss N_18 w=54.87u l=0.18u m=4
.ends sub4

xsub1 a b c 0 sub1
! L+ n! }) ~. r# d+ D% ^6 Sxsub2 b d e 0 sub2
xsub3 d f g 0 sub3
# D, N- a7 G9 G$ Yxsub4 f h i 0 sub4
1 r3 ]. a& I* H* Fcl h 0 1pf
6 N* e7 h3 _9 _1 p8 k% A

*****source******
6 g3 ?. m- H2 d/ t) t. x- ^% Kvdd c 0 1.8
vdd e 0 1.8
vdd g 0 1.8
vdd i 0 1.8
vgnd vss 0 0
vin a 0 pulse(0 1.8 1n 0.5n 0.5n 4.5n 10n)
: B( q4 h# E1 a2 K9 C1 L5 c4 {4 X*vin a 0 0.9
& k$ ?8 M4 D, {+ p
5 K$ F; M5 S) `& E! L