Experiment 2 Introduction to PSpice W T Yeung and R T Howe UC Berkeley EE 105 Fall 2005 1 0 Objective One of the CAD tools you will be using as an circuit designer is SPICE a Berkeleydeveloped industry standard program that is essential to the analysis and design of complex circuits In this experiment you will be introduced to the basics of SPICE You will learn the basics of representing circuit elements constructing the circuits and finally simulating the circuits 2 0 Material The version of SPICE you will be using is the student version of PSpice which is a free product of Cadence In more advanced courses you ll be using HSpice which is the full industrial strength version and definitely not free Fortunately we have a site license to the full Cadence CAD tools for research and education at Berkeley 3 0 Prelab Reading on line PSpice manual http www inst eecs berkeley edu ee105 fa06 PSPICE PspiceUserGuide pdf You can download the student version of PSpice from this web site http www orcad com Product Simulation PSpice eval asp Supplemental reading The Spice Home Page at http bwrc eecs berkeley edu Classes IcBook SPICE has an interactive tutorial The appendix to Experiment 1 is of general use but some of the information pertains to earlier releases of PSpice 1 of 8 Procedure FIGURE P1 1k V in 1k Y X 1pF 1k 1 Create a netlist for the circuit of Fig P1 You ll need to name both the elements and the nodes 2 We would like to have PSpice find the Bode plots for Vx Vin and Vy Vin Determine how to do this 3 If you have a PC run PSpice and generate the magnitude and phase Bode plots Compare your results with those you find by solving for Vx Vin analytically Save the file as your filename cir and bring it on a floppy disk to lab 4 0 Procedure 4 1 Transient Analysis 1 Solve the Prelab circuit on the PC at your lab station if you haven t already done it 2 Construct the PSpice file for the lowpass filter shown below We are interested in the transient analysis rather than viewing it as a filter Let the voltage waveform be a 1 kHz square wave that ranges from 0 to 5 V FIGURE 2 Lowpass Filter 10K vout vs 3 Your PSpice file should contain the following information Circuit information 2 of 8 Experiment 2 Introduction to PSpice 0 01 F Procedure tran statement for the times t 0 to t 10ms probe Lab Tip The voltage source has the following format Vname node node dc dc tran transient information The square wave in the above example can be modeled as either a pulse or a piecewise linear function This information goes in your voltage source statements 4 Launch PSpice by double clicking on its icon 5 Click on File and Open 6 Select the filename you assigned and PSpice will attempt to analyze the circuit 7 Click on File and Run Probe 8 Probe data files have a dat extension It should have been loaded automatically 9 Click on the Trace command followed by Add This will allow you to plot the volt ages and currents available in the circuit Lab Tip Probe can also plot mathematical expressions involving the voltages and currents You can use the cursor command from the Tools menu in probe to get x and y coordinates from the graph Labels and Titles can be inserted into your plots for clearer understanding These are accessible from the Tools menu 10 Print out your plot by clicking on File followed by Print 11 From the Plot menu select Transient This will tell probe to plot transient data and not ac data 12 Obtain a printout for both vout t and vs t 4 2 DC Analysis 1 The following circuit contains an n channel metal oxide silicon field effect transis tor n MOSFET You do not need to know the internal operations of the MOSFET in order to complete this part of the experiment Enter the circuit below in a SPICE deck Experiment 2 Introduction to PSpice 3 of 8 Appendix FIGURE 3 MOSFET Circuit to Generate its I V Characteristics ID1 Node 1 M1 Node 2 W L 4 5 m 1 5 m VDD VGS GND Node 0 2 Include in your SPICE deck the following dc lin VDD 0 5 1 VGS 0 5 1 This sweeps VDD from 0 to 5V in 1V interval for each value of VGS 0 to 5V in 1V intervals probe You will need to define the MOSFET s Level 1 PSpice model parameters Use Kp 60e 6 Vto 1 Lambda 0 05 and the defaults for the rest of the parameters See pages 239 245 of H S for information on the Level 1 MOSFET model 3 Run PSpice and Probe and plot the drain current of your transistor ID1 This will give you the MOSFET s I V characteristics Print a hardcopy Always include your input deck in your lab report 5 0 Appendix There are many versions of SPICE available PSPICE SPICE3 HSPICE etc Regardless of the version the structure of an input file is the same A SPICE simulation consists of 4 parts 2 Constructing the circuit 3 Specifying the type of analysis 4 Performing the simulation 5 Evaluating the results 5 1 Constructing the Circuit SPICE can simulate a wide variety of circuit elements In this tutorial we will introduce the elements which you will encounter in EE 105 5 1 1 Two Terminal Elements 4 of 8 Experiment 2 Introduction to PSpice Appendix Two terminal elements are specified by the and terminals In cases of passive element such as resistors and capacitors there is no distinction between the and terminals For voltage sources and current sources the order of the nodes determines the polarity of the voltage or the direction of the source FIGURE 4 Passive Two Terminal Elements Resistors Rname node node value Capacitors Cname node node value Voltage Source Vname node node value Current Source Iname node node value 5 1 2 Multi Terminal Elements FIGURE 5 Examples of Multiterminal Elements npn BJT and n channel MOSFET Collector Base Drain Bulk Gate Emitter Source Bipolar Transistors Qname collector node base node emitter node model type A bipolar transistor is specified by its collector base and emitter terminals The model type tells SPICE to refer to that particular model with its specific parameters MOSFETS Mname drain node gate node source node body node model type geometry A MOS transistor is specified by its drain gate source and body terminals along with the name of a model If the geometry is not specified it will have a gate length and Experiment 2 Introduction to PSpice 5 of 8 Appendix width of 1 m It is important to note that on a circuit the body is often not labeled as a terminal Most often for a NMOS the body is either tied to ground or to the source and for the PMOS the body is either tied to the power supply or …
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