问题的提出
在采用SIMetrix 8.3软件进行E类放大器的仿真过程中，用到了NEXPERIA公司的NMOS管器件PMH550UNE, 但在SIMetrix 8.3的库中没有该器件，因此需要导入第三方库文件.
通常的办法是从生产该器件的公司网站上下载器件库文件，导入到SIMetrix中. 库文件为后缀为*.lib 文件，同时导入器件的符号文件，后缀为 .sym。
但在NEXPERIA公司的网站上只能下载到NMOS器件PMH550UNE的SPICE的网表文件，如下所示：
********************************************************************************************************
*
* Nexperia PMH550UNE
* Polarity N - Channel
* Ratings 30V/550.0mOhm/1A
* Revision N#: 1.0
* Created on 2019-01-28 11:02:22
* Please visit www.nexperia.com for latest revision release
*
********************************************************************************************************
*
* Model generated by Nexperia
* Copyright(c) 2018
* All rights reserved
*
* Contains proprietary information which is the property of Nexperia.
*
********************************************************************************************************
.SUBCKT PMH550UNE D G S
* Package impedance
LD D 5 5.000p
RLD2 D 5 12.57m
RLD1 5 4 10.00u
LG G 1 218.2p
RLG G 1 548.3m
LS S 8 315.1p
RLS2 S 8 792.0m
RLS1 8 7 26.64m
* Drain,gate and source resistances
RD 3 4 416.4m TC= 2.582m,1.000n
RG 1 2 19.00
RS 6 7 1.000u
* Body Diode
RBD 9 4 327.5m TC= 4.000m,23.00u
DBD 7 9 D_DBD
RDS 7 4 1.948G TC= -5.000m
* Internal MOS
M1 3 2 6 6 MINT
* Gate leakage and gate capacitance
RGS 2 6 11.05MEG
CGS 2 6 26.60p
* CGD
C11 11 12 1E-12
V11 11 0 0Vdc
G11 3 2 VALUE {V(13,0)*I(V11)}
E11 12 0 3 2 1
E12 13 0 TABLE {V(12)}
+ (-4.5,75.0) (-1.56,75.0) (0.01,28.8995) (0.1,24.986) (0.2,21.397) (0.5,13.477) (1.0,9.4903) (2.0,7.4342999999999995) (3.0,6.5095) (4.0,5.9329) (5.0,5.5226) (6.0,5.2074) (8.0,4.741700000000001) (10.0,4.4043) (12.0,4.142799999999999) (15.0,3.84) (24.0,3.2755)
.MODEL MINT NMOS Vto= 870.5m Kp= 3.892 Nfs= 343.4G Eta= 0.000
+ Level= 3 Gamma= 0.000 Phi= 600.0m Is= 1.000E-24 UO= 600.0
+ Js= 0.000 Pb= 800.0m Cj= 0.000 Cjsw= 0.000 Cgso= 0.000 Cgdo= 0.000 Cgbo= 0.000
+ Tox= 100.0n Xj= 0.000
+ Vmax= 618.1
.MODEL D_DBD D Bv= 38.68 Ibv= 250.0u Rs= 1.000u Is= 3.412p
+ N= 1.070 M= 704.3m VJ= 200.0m Fc= 500.0m Cjo= 80.77p Tt= 18.50n
.ENDS PMH550UNE
********************************************************************************************************
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*
********************************************************************************************************
现需要将该网表文件导入到SIMetrix中。
解决方法
下图为E类放大器的SIMetrix的仿真原理图，任意从库中选择一NMOS管，如信号BSC12DN20NS3_L0, 如下如Q1器件.
右键Q1器件，选择View/Edit model, 如下图所示
上栏为Global library model, 用户不能够编辑，下栏为Local model, 用户可编辑.
将需要仿真的器件PMH550UNE的SPICE网表文件内容覆盖到下栏中. 同时做以下修改：
- 将.SUBCKT PMH550UNE D G S行的内容改为：.SUBCKT BSC12DN20NS3_L0-Q1 drain gate source，注意，Q1为器件在原理图中的标号，要与原理图对应，否则会出现找不到…的错误.
- 将
*Package impedance
LD D 5 5.000p
RLD2 D 5 12.57m
RLD1 5 4 10.00u
LG G 1 218.2p
RLG G 1 548.3m
LS S 8 315.1p
RLS2 S 8 792.0m
RLS1 8 7 26.64m
中的D改为drain, G改为gate, S改为source
3. 将 .ENDS PMH550UNE 行的内容改为 .ENDS BSC12DN20NS3_L0
仿真测试
在Q1的Edit Model栏中选择Use global library model, 即采用BSC12DN20NS3_L0进行仿真，结果如下图所示.
选择Use local model, 即选择PMH550UNE进行仿真，仿真结果如下图所示：
