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Comparion of 1 , 2 and 3 Generation ModelsFamily of Curves, Id-Vgs, Sub-Vt
Verification of Resistor and Capacitor ValuesRing Oscillator Gate Delay td
Circuit ExamplesInverter with HysteresisRC OscillatorTwo Phase ClockOp AmpDiode Temperature Sensor
SPICE Examples
INTRODUCTION
SPICE (Simulation Program for Integrated Circuit Engineering) is a general-purpose circuit simulation program for non-linear DC, non-linear transient, and linear AC analysis. Circuits may contain resistors, capacitors, inductors, mutual inductors, independent voltage and current sources, four types of dependent sources, transmission lines, switches, and several semiconductor devices: including diodes, BJTs, JFETs, MESFETs, and MOSFETs. Circuits with large numbers
BJTs, JFETs, MESFETs, and MOSFETs. Circuits with large numbers of all types of components can be simulated.
SPICE input files and output files are simple text files (e.g. name.txt)
Input files include a TITLE, circuit description NET LIST, analysis directives (COMMANDS), and lists of other text files to include (INC) such as model libraries (LIB) and an END command.
SPICE Examples
INTRODUCTION
PSpice Lite 9.2 is one of the OrCAD family of products, from Cadence Design Systems, Inc., offering a complete suite of electronic design tools. It is free and includes limited versions of OrCAD Capture, for schematic capture, PSpice for analog circuit simulation and Pspice A/D for mixed analog and digital circuit simulation. PSpice Lite 9.2 is limited to 64 nodes, 10 transistors, two operational amplifiers and 65 primitive digital devices. See page 35 (xxxv) of the PSpice Users Guide.
LT SPICE – is a free SPICE simulator with schematic capture from Linear Technology. It is quite similar to Pspice Lite but is not limited in the number of devices or nodes. Linear Technology (LT) is one of the industry leaders in analog and digital integrated circuits. Linear Technology provides a complete set of SPICE models for LT components.
WINSPICE – is a low cost fully capable SPICE simulator for windows computers. The full version is approximately $75. It does not include a schematic editor. (but is
available from third party)
SPICE Examples
EXAMPLE OF SIMPLE SPICE INPUT FILE
DR FULLER - SIMPLE EXAMPLE TITLE* THE FIRST LINE IS THE TITLE* LINES THAT START WITH * ARE COMMENT LINES AND DO NOTHING* UPPER AND lower case text ARE TREATED THE SAME* CIRCUIT IS DESCRIBED BELOW (NET LIST)R1 1 0 2K ; resistor R1 between node 1 and zero has value 2000 ohmsR2 2 1 3KV1 2 0 DC 5 ; Voltage source V1 is a DC source of 5 volts*
** REQUESTED ANALYSIS (DIRECTIVES OR COMMANDS).DC V1 0 5 .1 ; find all node voltages and branch currents for V1 starting at 0 and * incrementing by 0.1 volts ending at 5 volts.PLOT DC V(1)**.INCLUDE File_name.txt ;(none for this example)*.END
SPICE Examples
CREATING THE INPUT FILE
The input file can be generated from a schematic capture program, or just typed in a text editor such as “Notepad” or “WordPad”
R2 2 1 3KV1 2 0 DC .DC V1 0 5 .1 .PLOT DC V(1).END
0
5V
V1
R2
3K
+
-
SPICE Examples
WINSPICE3
WinSpice3 is a general-purpose circuit simulation program for non-linear DC, non-linear transient, and linear AC analyses. Circuits may contain resistors, capacitors, inductors, mutual inductors, independent voltage and current sources, four types of dependent sources, lossless and lossy transmission lines (two separate implementations), switches, uniform distributed RC lines, and the five most common semiconductor devices: diodes, BJTs, JFETs, MESFETs, and MOSFETs.
It can be downloaded and installed onto personal computers at http://www.winspice.com . When the full version v1.05.01 is installed, it should
http://www.winspice.com . When the full version v1.05.01 is installed, it should be updated to v1.05.07, which is the latest version available for now.
WinSpice basically Spice3F4 for Windows 32bit systems. However, it contains several enhancements over the original Berkeley Spice3F4.
WinSpice iteself does not contain a schematic editor (capture/edit). However, 3rd part schematic editors can be linked to WinSpice. A schematic editor which uses WinSpice for its simulation engine is available at http://www.5spice.com/. These editors provide a convenient way to draw a schematic and create a net list.
SPICE Examples
RUNNING WINSPICE
Once WinSpice is installed click on your shortcut or start WinSpice from the start programs menu.
A dialog box and WinSpice -> prompt should appear.
Type source path_to_your_input_file.txt Press Enter
PSpice Lite 9.2 is one of the OrCAD family of products offering a complete suite of electronic design tools. These products are available from Cadence Design Systems, Inc. PSpice Lite 9.2 includes limited versions of OrCAD Capture, for schematic capture, PSpice for analog circuit simulation and Pspice A/D for mixed analog and digital circuit simulation. PSpice Lite 9.2 is limited to 64 nodes, 10 transistors, two operational amplifiers and 65 primitive
analog and digital circuit simulation. PSpice Lite 9.2 is limited to 64 nodes, 10 transistors, two operational amplifiers and 65 primitive digital devices. See page 35 (xxxv) of the PSpice Users Guide.
SPICE Examples
BEFORE YOU START
It might be good to set up some folders for your SPICE projects
Orcad PSpice has many model libraries that can be included with a SPICE input file. You could also create your own models as a simple text file and include that file with a SPICE input file for either PSpice or WinSpice.
In SPICE a transistor is defined by its name and associated properties and its model. Its name and associated properties is given in the input file net list. Its model is given in the included library or model file or pasted into the input file.
note: PSpice does not recognize level 49, WinSpice does not recognize level 7
SPICE Examples
RIT MOSFET SPICE MODELS
*SPICE MODELS FOR RIT DEVICES - DR. LYNN FULLER 2-5-2010*LOCATION DR.FULLER'S COMPUTER DESKTOP/SPICE/MODELS/FULLER_RIT_MOSFET_MODELS.txt*SEE: http://people.rit.edu/lffeee/CMOS.htm**LIST OF DEVICES/MODELS INCLUDED IN THIS LIBRARY** RITMEMDIODE DIODE MODEL FOR EMCR870 MEMS FABRICATION COURSE* RITPMOS7 LEVEL 7 MODEL FOR PMOSFET MADE IN RIT PMOS PROCESS* RITPMOS49 LEVEL 49 MODEL FOR PMOSFET MADE IN RIT PMOS PROCESS* RITSUBN1 LEVEL 1 MODEL FOR NMOSFET MADE IN RIT SUB-CMOS PROCESS* RITSUBP1 LEVEL 1 MODEL FOR PMOSFET MADE IN RIT SUB-CMOS PROCESS
* RITSUBN1 LEVEL 1 MODEL FOR NMOSFET MADE IN RIT SUB-CMOS PROCESS* RITSUBP1 LEVEL 1 MODEL FOR PMOSFET MADE IN RIT SUB-CMOS PROCESS* RITSUBN3 LEVEL 3 MODEL FOR NMOSFET MADE IN RIT SUB-CMOS PROCESS* RITSUBP3 LEVEL 3 MODEL FOR PMOSFET MADE IN RIT SUB-CMOS PROCESS* RITSUBN7 LEVEL 7 MODEL FOR NMOSFET MADE IN RIT SUB-CMOS PROCESS* RITSUBP7 LEVEL 7 MODEL FOR PMOSFET MADE IN RIT SUB-CMOS PROCESS* RITSUBN49 LEVEL 49 MODEL FOR NMOSFET MADE IN RIT SUB-CMOS PROCESS* RITSUBP49 LEVEL 49 MODEL FOR PMOSFET MADE IN RIT SUB-CMOS PROCESS* CMOSN LEVEL 2 MODEL FOR NMOSFET ORBIT SEMICONDUCTOR* CMOSP LEVEL 2 MODEL FOR PMOSFET ORBIT SEMICONDUCTOR* EENMOS LEVEL=2 MODEL FOR NMOSFET USED IN EEEE481 ELECTRONICS I* QRITNPN BJT MODEL USED IN EMCR482 ELECTRONICS II** note: Level 7 and Level 49 are the same except for two extra parameters in level 49* PSpice does not recognize level 49, WinSpice does not recognize level 7*
.model RITMEMDIODE D IS=3.02E-9 N=1 RS=207+VJ=0.6 CJO=200e-12 M=0.5 BV=400** From Electronics I EEEE481.model EENMOS NMOS LEVEL=2+VTO=0.7 KP=25E-6 LAMBDA=0.02 GAMMA=0.9 TOX=90E-9 NSUB=3.7E15** From Electronics II EEEE482 BJT Model.MODEL QRITNPN NPN (BF=416 IKF=.06678 ISE=6.734E-15 IS=6.734E-15 NE=1.259 RC=1 RB=10 VA=109)
SPICE Examples
IMPORTING THE INCLUDE FILES INTO LTSPICE
To Import the model file:1. Copy down the previous slide into a txt file using Notepad/Wordpad2. Save your model file as either a .txt file or a .inc file somewhere on your computer.3. In LTSPICE, add a SPICE Directive. This can be done either by pressing the ‘T’ button or clicking on the text button and selecting the radio button that says “SPICE directive”
radio button that says “SPICE directive”4. Type in “.inc” in the textbox.5. Click the OK button and place the directive somewhere on the circuit schematic.6. Right-Click on the text you just placed and click the browse button.7. Navigate to your saved model file, open it, and click the OK button again. Your models are now loaded into your circuit.
To use the imported file, add the device, right click on it’s name (usually the name on bottom), and change it to the name used in the included file (RITMEMDIODE for example)
From SimulationGiven model on left with L=10u and W=1000u
Note: not a very good match. Increase L?
SPICE Examples
CONCLUSION FROM DC MODEL COMPARISON
Third generation MOSFET models such as Level 7 for OrCAD PSPICE or Level 49 models for WinSpice give better results than any of the 1st or 2nd generation models. These models are different for different processes (such as RIT’s Sub-CMOS 150 or RIT’s Adv-CMOS 150 processes)
IDS VS. VGS FOR RIT SUB-CMOS NMOSFET, Dr. Lynn Fuller, 1-15-2007*LINE ABOVE IS TITLE**START WIN SPICE AND ENTER LOCATION AND NAME OF INPUT FILE*THIS FILE IS ID-VD-N.TXT*EXAMPLE: winspice> source c:/spice/ID-VD-N.txt**THE TRANSISTOR MODELS ARE IN THE FILE NAMED BELOW.INCLUDE E:\SPICE\WINSPICE\RIT_MICROE_MODELS.TXT**CIRCUIT DESCRIPTION**VOLTAGE SOURCESV1 1 0 DC 0.1V2 2 0 DC 1
where ID is a dependent current source using simple long channel equations.
SPICE Examples
AC MODEL FOR MOSFETS
The parameters that effect the AC response of a MOSFET are the resistance and capacitance values.
RS,RS Source/Drain Series Resistance, ohmsRSH Sheet Resistance of Drain/Source, ohmsCGSO,CGDO Zero Bias Gate-Source/Drain Capacitance, F/m of widthCGBO Zero Bias Gate-Substrate Capacitance, F/m of lengthCJ DS Bottom Junction Capacitance, F/m2CJSW DS Side Wall Junction Capacitance, F/m of perimeter
CJ DS Bottom Junction Capacitance, F/m2CJSW DS Side Wall Junction Capacitance, F/m of perimeterMJ Junction Grading Coefficient, 0.5MJSW Side Wall Grading Coefficient, 0.5
These are combined with the transistors L, W Length and WidthAS,AD Area of the Source/DrainPS,PD Perimeter of the Source/DrainNRS,NRD Number of squares Contact to Channel
Three Stage Ring Oscillator with Transistor Parameters for 73 Stage Ring Oscillator and Supply of 5 volts
td = T / 2N = 5.5nsec / 2 / 3
td = 0.92 nsecMeasured td = 0.718 nsec @ 5 V
SPICE Examples
CONCLUSION
Since the measured and the simulated gate delays, td are close to correct, then the SPICE model must be close to correct. The inverter gate delay depends on the values of the internal capacitors and resistances of the transistor.
These are combined with the transistors L, W Length and WidthAS,AD Area of the Source/DrainPS,PD Perimeter of the Source/DrainNRS,NRD Number of squares Contact to Channel
SPICE Examples
INVERTER WITH HYSTERESIS
INVERTER WITH HYSTERESIS USING FOR RIT SUB-CMOS NMOSFET, Dr. Lynn Fuller, 1-15-2007
*LINE ABOVE IS TITLE
*
*START WIN SPICE AND ENTER LOCATION AND NAME OF INPUT FILE
INVERTER WITH HYSTERESIS USING FOR RIT SUB-CMOS NMOSFET, Dr. Lynn Fuller, 1-15-2007*START WIN SPICE AND ENTER LOCATION AND NAME OF INPUT FILE*THIS FILE IS ID-VD-N.TXT*EXAMPLE: winspice> source c:/spice/Hysteresis.txt**THE TRANSISTOR MODELS ARE IN THE FILE NAMED BELOW.INCLUDE G:\SPICE\WINSPICE\RIT_MICROE_MODELS.TXT**VOLTAGE SOURCESV1 1 0 DC 6*TRANSISTORSM1 7 2 0 0 RITSUBN49 L=2U W=64U ad=96e-12 as=96e-12 pd=44e-6 ps=44e-6 nrd=0.025 nrs=0.025M2 3 2 7 0 RITSUBN49 L=2U W=16U ad=96e-12 as=96e-12 pd=44e-6 ps=44e-6 nrd=0.025 nrs=0.025
1. MOSFET Modeling with SPICE, Daniel Foty, 1997, Prentice Hall, ISBN-0-13-227935-5
2. Operation and Modeling of the MOS Transistor, 2nd Edition, Yannis Tsividis, 1999, McGraw-Hill, ISBN-0-07-065523-5
3. UTMOST III Modeling Manual-Vol.1. Ch. 5. From Silvaco International.4. ATHENA USERS Manual, From Silvaco International.5. ATLAS USERS Manual, From Silvaco International.6. Device Electronics for Integrated Circuits, Richard Muller and Theodore