Issue link: https://resources.pcb.cadence.com/i/1180526
PSpice User Guide Monte Carlo and sensitivity (worst-case) analyses October 2019 595 Product Version 17.4-2019 © 1999-2019 All Rights Reserved. Figure 13-14 Amplifier netlist and circuit file. The first .MODEL statement leaves the nominal value of Rb2 at 720 ohms. The sensitivity analysis increments R by a small amount and checks its effect on Vm([OUT]). This slight increase in R causes an increase in the base bias voltage of the BJT, and increases the amplifier's gain, Vm([OUT]). The worst-case analysis correctly sets R to its minimum value for the lowest possible Vm([OUT]) (see Figure 13-15). The second .MODEL statement scales the nominal value of Rb2 by 1.1 to approximately 800 ohms. The gain still increases with a small increase in R, but a larger increase in R increases the base voltage so much that it drives the BJT into saturation and nearly eliminates * Worst-case analysis comparing monotonic and non-monotonic * output with a variable parameter .lib ***** Input signal and blocking capacitor ***** Vin In 0 ac 1 Cin In B 1u ***** "Amplifier" ***** * gain increases with small increase in Rb2, but * device saturates if Rb2 is maximized. Vcc Vcc 0 10 Rc Vcc C 1k Q1 C B 0 Q2N2222 Rb1 Vcc B 10k Rb2 B 0 Rbmod 720 .model Rbmod res(R=1 dev 5%) ; WC analysis results ; are correct * .model Rbmod res(R=1.1 dev 5%) ; WC analysis misled ; by sensitivity ***** Load and blocking capacitor ***** Cout C Out 1u Rl Out 0 1k * Run with either the .STEP or the .WC, but not both. * This circuit file is currently set up to run the .STEP * (.WC is commented out) **** Parametric Sweep—providing plot of Vm([OUT]) vs. Rb2 **** .STEP Res Rbmod(R) 0.8 1.2 10m ***** Worst-case analysis ***** * run once for each of the .model definitions stated above) * WC AC Vm([Out]) min range 99k 101k list output all .AC Lin 3 90k 110k .probe .end