Spice1ans

# Spice1ans - ECE 255 ELECTRONIC ANALYSIS AND DESIGN Fall...

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ECE 255 ELECTRONIC ANALYSIS AND DESIGN Fall 2009 S PICE D ESIGN P ROJECT #1 Due Friday, October 2, 2009 Measurement results in RED 5:00 p.m. Room MSEE 180 Drop Box Development of D.C. and Hybrid- π models for a 2N3704 Bipolar Transistor. (Dry lab of ECE 208 Experiments #9A and #11) This exercise will use the PSpice model MPS3704 (which is actually a 2N3704 in a different package). The model parameters from Cadence PSpice are given below. .model MPS3704 NPN(Is=26.03f Xti=3 Eg=1.11 Vaf=90.7 Bf=736.1K Ne=1.232 + Ise=26.03f Ikf=.1983 Xtb=1.5 Br=1.024 Nc=2 Isc=0 Ikr=0 Rc=.5 + Cjc=11.01p Mjc=.3763 Vjc=.75 Fc=.5 Cje=24.07p Mje=.3641 Vje=.75 + Tr=233.8n Tf=1.03n Itf=0 Vtf=0 Xtf=0 Rb=10) 1. To verify that your transistor model is correct, plot the input characteristics @ V CE = 2 V and the output characteristics for I B = 20, 40, 60, 80, and 100 μ A for CE 0 V 10V to obtain the plots shown below. 2. The model for the forward biased Base-Emitter junction consists of a series D.C. voltage source, V 0 , and series resistor, R BB connected between the Base and Emitter terminals. Using your plot of the transistor input characteristics determine and list appropriate values for both V 0 and R BB at operating points characterized by I B = 20 μ A and 50 μ A. I B V BE R BB V 0 20 μ A .652 V 1.60 k .620 V 50 μ A .681 V .645 k .649 V NOTE: Remember that the d( ) operator can be used to find the derivative of a PSpice curve. Additional copies of the tables appear on the last page for use in your report. Base Current Collector Current

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3. Plot the V-I characteristics (using “Add Trace …” in the plot window) of your models on the input characteristics as shown below. 4. The output characteristics are modeled by the parallel combination of an independent current source, I CEO , a dependent current source, β dc I B , and a resistor, R d . In this case, the independent current source, I CE0 , can be considered unimportant. Determine and list values for the control of the independent source, β dc , and the parallel resistor, R d . I B β dc R d 20 μ A 113 39.8 k 40 μ A 130 17.2 k 60 μ A 141 10.6 k 80 μ A 149 7.57 k 100 μ A 154 5.84 k 5. Using the equation, C dc B CE d I I V R = β + , plot the characteristics of the models you have created (using “Add Trace …” in the plot window) on the output characteristics of the transistor as shown below. 6. On a second plot, extend the sweep to negative voltages and show that your model characteristics converge to a single point; then using the cursor, mark that point, the Early Voltage, ( –V A ). Base Current Collector Current Collector Current
Vcc R2 100k Rs 33k 0 Vbb 0 Vcc Rc 0 0 MPS3704 0 Vcc 5Vdc R1 22k Vs 1Vac 0Vdc Vce Vbb Vbb 0 0 MPS3704 Vbb 0 Rc Vref 2Vdc Vbb 0 Rs 33k Vcc Vce - + + - E E Vs 1Vac 0Vdc Vcc 5Vdc Vce 0 0 R2 100k Vcc R1 22k Determination of the Hybrid- π model parameters In the ECE 208 Experiment #11, you will build the following circuit (using a 2N3704 on place of the MPS3704): In the lab, you will insert different values of R C and adjust V BB to make V CE = 2 V before each set of measurements to determine the Hybrid- π model parameters. You could perform this same procedure

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