Listing 3: Simple Differential Pair Circuit—Version 2
* set options
.opt nopage
.width in=72
.width out=80
* analysis control
.dc vin -0.15 0.15 0.001
.tf v(out2) vin
.ac dec 10 1 10ghz
.tran 5ns 2500ns 0 0.5ns
* current and voltage sources
iee 3 vee 1m
vin input 0 0 sin(0 0.3 5meg) ac 1
vcc vcc 0 5
vee vee 0 -5
* circuit elements
rb1 1 input 1
rb2 2 0 1
rl1 out1 vcc 5k
rl2 out2 vcc 5k
q1 out1 1 3 bjt
q2 out2 2 3 bjt
* models
.model bjt npn(bf=80 rb=100 ccs=2pf
+ tf=0.3ns tr=6ns cje=3pf cjc=2pf
+ va=50)
* keep SPICE happy
.end