A BJT Differential Pair

** Circuit Description **
* power supply
Vdd 6 0 DC +5V
Vee 7 0 DC -5V
* differential-mode signal level
Vd 101 0 DC 0V
Rd 101 0 1
EV+ 1 100 101 0 +0.5
EV- 2 100 101 0 -0.5
* common-mode signal level
Vcm 100 0 DC 0V
* monitor collector currents of Q1 and Q2
Vic1 6 4 0
Vic2 6 5 0
* differential pair
Q1 4 1 3 npn_transistor
Q2 5 2 3 npn_transistor
* bias source
I 3 7 DC 1mA
* transistor model statements
.model npn_transistor npn ( Is=14fA Bf=100 VAf=100V )
** Analysis Requests **
.DC Vcm -5V +6V 100mV
** Output Requests **
.PLOT DC I(Vic1) I(Vic2)
.probe
.end