SPICE-Simulation using LTspice IV

1 1 SPICE-Simulation usingLTspice IV Tutorial for successful simulation of electronic circuits with the free full version of LTspice IV (before named SwitcherCAD ), available at Linear Technologies ( ). Version by Gunthard Kraus, Elektronikschule Tettnang, Germany,Guest Lecturer at the DHBW (Duale Hochschule Baden-Wuerttemberg), Friedrichshafen, Germany Email: or ~krausgDecember 15th, 2010 2 Contents Page1. Introduction 5 2. Installation 5 3. Exercises with the included Example Astable Multivibrator 5 using Schematic and simulation 5 Presentation of simulation Results 7 Deleting Curves 8 Changing Curve Colours 9 Changing the simulation Time 10 Changing Current- or Voltage Ranges 12 using Cursors 14 Working with one Cursor 14 Working with two Cursors 14 Differential Measurements

2 15 Current Measurements 16 Changing Part Values 174. Project 1: RC Lowpass Filter 18 Drawing the Circuit Diagram with the Editor 18 Changing Part Values 19 Time Domain simulation : non-repetitive Signals at the Input 20 Step Response 20 Switching ON and OFF 22 Impulse Response 23 Time Domain simulation : using Periodic Signals at the Input 26 Sine Wave (f = 1591 Hz) 26 Square Wave (f = 1591 Hz) 27 Triangle Wave (f = 1591 Hz) Frequency Domain simulation : AC Sweep 29 5.

3 FFT (= Fast Fourier Transform) 316. Project 2: Rectifiers 34 Simple Rectifier without Transformer 34 Important: creating SPICE Model and Symbol for a Transformer 35 The easiest Solution: a simple ideal Transformer Creation of the SPICE Model for a real Two Windings Transformer 35 Creation of the Symbol for a Two Windings Transformer 35 One Pulse Rectifier with Transformer 38 Rectifier with Diode 1N4007 40 Two Pulse Rectifier with Transformer 42 7.

4 Project 3: Three Phase AC-system Schematic and simulation 44 Rectifier Bridge for Three Phase AC Systems (= dynamo in a modern car or motorcycle) 45 38. Project 4: U-I-Curves of Parts 47 Resistor 47 Diode 48 NPN Transistor 49 N Channel junction FET 519. Project 5: Transistor Circuits 52 One Stage Amplifier 52 Time Domain simulation 52 Frequency Domain simulation : AC Sweep Two Stage Broadband Amplifier with Feedback 55 Task Circuit Diagram for simulation 55 Time Domain simulation 56 DC Bias 57 Frequency Domain Dimulation.

5 AC Sweep 59 Parametric Sweep 6010. Project 6: OPA Circuits 62 Starting with an Inverting Amplifier 62 Preparing a SPICE Model from the Internet 62 Gainblock for 1kHz to 30 MHz with OPA355 64 simulation using the selfmade OPA355 Subcircuit Model 64 Usage of Labels 67 11. Project 7: DC-DC Converters 69 Model for the Power-MOSFET IRFZ44N 69 The Step Up Converter 71 The Flyback Converter 73 The Step Down Converter 7512.

6 Project 8: Thyristor Circuits Thyristor Model 77 Switching Resistive Loads 78 Switching Inductive Loads 79 Circuit with Gate-Transformer 80 13. Project 9: Echos on Transmission Lines Transmission Lines -- only two Wires? 81 Echoes 83 simulation of the Example with LTspice 85 Open or Short Circuit at Cable s End 88 Lossy Cables (e.)

7 G. RG58 / 50 ) How can I simulate a RG58 Coaxial Cable? simulation of Cable Loss at 100 MHz Feeding the RG58 Cable Entry with a Pulse Voltage 94 A Short Circuit at RG58 Cables s End 9514. Project 10: S-Parameters 96 Echoes once again, but with more System (= S parameters) Example: 110 MHz Tchebyshev Lowpass Filter (LPF) 99 415. Project 11: Double Balanced Mixer 103 Fundamentals and Informations 103 The Ring Modulator 104 The necessary Transformers 105 DBM simulation with ideal Transformers 10616.

8 Project 12: Simulations with Digital Circuits What you should know before 108 Simple start: the inverter (= NOT) 109 AND- and NAND-Gate 110 D Flipflop 111 Three Stage Frequency Divider with D Flipflops 112 17. Project 13: Noise simulation 113 Fundamentals 113 Noise -- where does it come from?

9 Other Sources of Noise 115 Noise Temperature and Noise Factor for a Twoport System 116 simulation of the Spectral Noise Densitiy 116 simulation of the Noise Figure NF (in dB) 119 18. simulation of a Sine Oscillator 123 19. Signals and Harmonics 128 Fundamentals 128 simulation of a Single Pulse Spectrum 131 simulation of a Periodic Pulse Spectrum 133 An Ideal Sine Wave 134 The One Side Clipped Sine Wave 135 The Symmetrically Clipped Sine Wave

10 136 20. The Secret of the Impulse Response 137 First example: Dirac Pulse applied to a 160Hz RC Lowpass Filter 138 Second Example: Dirac Test of a 110 MHz Lowpass Filter (see Chapter ) 142 Simulating S21 (= Forward Transmission) 142 simulation of S11 (= input reflection) or S22 (= output reflection) 147 21. Modulation Principle of Amplitude Modulation (AM) 149 Amplitude Shift Keying (ASK) 151 Frequency modulation (FM) Generating an FM signal using the SFFM voltage supply 152 Frequency Shift Keying (FSK) 154 51.