Example 7.10c: A Modified Differential Amplifier

** Circuit Description **
* power supplies
Vcc 1 0 DC +10V
* input signal source
Vs 6 0 AC 1V
Rs 6 5 10k
* differential pair
Rc1 1 2 10k
Q1 1 5 4 Q2N3904
Q2 2 0 4 Q2N3904
* current biasing
Ibias 4 0 1mA
*
* transistor model statement for 2N3904
.model Q2N3904  NPN (Is=6.734f Xti=3 Eg=1.11 Vaf=74.03 Bf=416.4 Ne=1.259
+                    Ise=6.734f Ikf=66.78m Xtb=1.5 Br=.7371 Nc=2 Isc=0 Ikr=0 Rc=1
+                    Cjc=3.638p Mjc=.3085 Vjc=.75 Fc=.5 Cje=4.493p Mje=.2593 Vje=.75
+                    Tr=239.5n Tf=301.2p Itf=.4 Vtf=4 Xtf=2 Rb=10)
** Analysis Requests **
.OP
.AC DEC 10 1Hz 100MegHz 
** Output Requests **
.PLOT AC VdB(2) Vp(2)
.probe
.end