Spice Seminar Simulation Program with Integrated Circuit Emphasis

Generating a Netlist SPICE Netlist Text file used for simulation Simulate Generate Netlist (SPICE Netlist Different flavors Quite similar) Schematic Entry (Common Data format: EDIF)

Netlist Format C B E model name Q1 Vo Vin 0 Q2N2222 R1 Vo Vcc 1K V1 Vin 0 V2 Vcc 0

Number format m 10-3 u 10-6 n 10-9 p 10-12 f 10-15 K 103 Meg 106 G 109 Alternative Notation 1e3 Note 10M is the same as 10m!

Which is more readable/maintanable?

Examples of Types of Spice Simulations Bias Point DC Sweep Transient Analysis AC sweep/Noise Secondary (nested) sweeps Parametric Temperature Monte Carlo You may find this tutorial helpful at the end of the term

DC sweep Result Output as a function of Vin Vo V1

Parametric Sweep – creating a variable

Nested Sweep

Bias Point Simulation In a bias point simulation capacitors are modeled as open circuits

Both transient and AC sweeps can be used to determine gains, input and output impedances

Transient and AC Sweep Overview Transient Results Time varying inputs (ex. Sinusoidal, digital clock) Output as a function of time t t AC Sweep Results Vo Multiple sinusoidal inputs each with a different frequency Output as a function of freq. freq

AC Sweep Configuration for Determining Voltage Gain (Av) and Input Impedance (Ri) DC offset is zero “small signal” is 1 Important: when simulating the start frequency cannot be zero!

Resulting Simulation

Plotting Av and Ri

AC Sweep Configuration for Determining Output Impedance (Ro) DC offset is zero “small signal” is applied here (Vo) DC offset is zero “small signal” is zero (Vin = 0)

Transient Sweep Vsin