* SPICE netlist
R2 0 OUT {Rc}
R3 0 _OUT {Rc}
V_IN IN 0 PULSE(0 0.45 0 1n 1n 48n 100n)
V_REF V_REF 0 {V_REF}
V_VCC VCC 0 3.3
R5 0 OUT2 {Rc}
R6 0 _OUT2 {Rc}
Q2 OUT IN N001 0 2N3906
Q3 _OUT V_REF N001 0 2N3906
I1 VCC N001 {Ig}
I2 VCC N002 {Ig}
Q1 OUT2 _OUT N002 0 2N3906
Q4 _OUT2 V_REF N002 0 2N3906
R1 0 OUT3 {Rc}
R4 0 _OUT3 {Rc}
I3 VCC N003 {Ig}
Q5 OUT3 OUT N003 0 2N3906
Q6 _OUT3 V_REF N003 0 2N3906
.tran 1u
;.step param V_REF 0 3.3 0.1
.param V_REF 0.225
.step temp -25 125 25
.param Rc 220
.param Ig 2m

* LTspice schematic (.asc)
Version 4
SHEET 1 3648 816
WIRE -1104 -408 -1200 -408
WIRE -704 -408 -1104 -408
WIRE 288 -408 -704 -408
WIRE 1264 -408 288 -408
WIRE -704 -328 -704 -408
WIRE 288 -328 288 -408
WIRE 1264 -328 1264 -408
WIRE -704 -200 -704 -248
WIRE -704 -200 -816 -200
WIRE -608 -200 -704 -200
WIRE 288 -200 288 -248
WIRE 288 -200 176 -200
WIRE 384 -200 288 -200
WIRE 1264 -200 1264 -248
WIRE 1264 -200 1152 -200
WIRE 1360 -200 1264 -200
WIRE -816 -72 -816 -200
WIRE -608 -72 -608 -200
WIRE 176 -72 176 -200
WIRE 384 -72 384 -200
WIRE 1152 -72 1152 -200
WIRE 1360 -72 1360 -200
WIRE -1024 -24 -1152 -24
WIRE -880 -24 -1024 -24
WIRE -416 -24 -544 -24
WIRE -352 -24 -416 -24
WIRE 112 -24 -48 -24
WIRE 576 -24 448 -24
WIRE 640 -24 576 -24
WIRE 1088 -24 928 -24
WIRE 1552 -24 1424 -24
WIRE 1616 -24 1552 -24
WIRE -608 56 -608 24
WIRE -368 56 -608 56
WIRE -48 56 -48 -24
WIRE -48 56 -368 56
WIRE 384 56 384 24
WIRE 624 56 384 56
WIRE 768 56 624 56
WIRE 1360 56 1360 24
WIRE 1600 56 1360 56
WIRE 1744 56 1600 56
WIRE -816 104 -816 24
WIRE -368 104 -816 104
WIRE -48 104 -368 104
WIRE 176 104 176 24
WIRE 624 104 176 104
WIRE 848 104 624 104
WIRE 1152 104 1152 24
WIRE 1600 104 1152 104
WIRE 1824 104 1600 104
WIRE -816 152 -816 104
WIRE -608 152 -608 56
WIRE 176 152 176 104
WIRE 384 152 384 56
WIRE 1152 152 1152 104
WIRE 1360 152 1360 56
WIRE -48 296 -48 104
WIRE 928 296 928 -24
WIRE 928 296 -48 296
WIRE -816 344 -816 232
WIRE -816 344 -1200 344
WIRE -608 344 -608 232
WIRE -608 344 -816 344
WIRE 176 344 176 232
WIRE 176 344 -608 344
WIRE 384 344 384 232
WIRE 384 344 176 344
WIRE 1152 344 1152 232
WIRE 1152 344 384 344
WIRE 1360 344 1360 232
WIRE 1360 344 1152 344
WIRE -1200 408 -1200 344
FLAG -1824 -248 0
FLAG -1824 136 0
FLAG -1824 -40 0
FLAG -1824 -328 VCC
FLAG -1104 -408 VCC
FLAG -1024 -24 IN
FLAG -368 104 OUT
FLAG -368 56 _OUT
FLAG -416 -24 V_REF
FLAG -1824 -120 V_REF
FLAG 624 104 OUT2
FLAG 624 56 _OUT2
FLAG 576 -24 V_REF
FLAG -1824 56 IN
FLAG -1200 408 0
FLAG 1600 104 OUT3
FLAG 1600 56 _OUT3
FLAG 1552 -24 V_REF
SYMBOL res -832 248 M180
SYMATTR InstName R2
SYMATTR Value {Rc}
SYMBOL res -624 248 M180
SYMATTR InstName R3
SYMATTR Value {Rc}
SYMBOL voltage -1824 40 R0
SYMATTR InstName V_IN
SYMATTR Value PULSE(0 0.45 0 1n 1n 48n 100n)
SYMBOL voltage -1824 -136 R0
SYMATTR InstName V_REF
SYMATTR Value {V_REF}
SYMBOL voltage -1824 -344 R0
SYMATTR InstName V_VCC
SYMATTR Value 3.3
SYMBOL res 160 248 M180
SYMATTR InstName R5
SYMATTR Value {Rc}
SYMBOL res 368 248 M180
SYMATTR InstName R6
SYMATTR Value {Rc}
SYMBOL pnp -880 24 M180
SYMATTR InstName Q2
SYMATTR Value 2N3906
SYMBOL pnp -544 24 R180
SYMATTR InstName Q3
SYMATTR Value 2N3906
SYMBOL current -704 -328 R0
SYMATTR InstName I1
SYMATTR Value {Ig}
SYMBOL current 288 -328 R0
SYMATTR InstName I2
SYMATTR Value {Ig}
SYMBOL pnp 112 24 M180
SYMATTR InstName Q1
SYMATTR Value 2N3906
SYMBOL pnp 448 24 R180
SYMATTR InstName Q4
SYMATTR Value 2N3906
SYMBOL res 1136 248 M180
SYMATTR InstName R1
SYMATTR Value {Rc}
SYMBOL res 1344 248 M180
SYMATTR InstName R4
SYMATTR Value {Rc}
SYMBOL current 1264 -328 R0
SYMATTR InstName I3
SYMATTR Value {Ig}
SYMBOL pnp 1088 24 M180
SYMATTR InstName Q5
SYMATTR Value 2N3906
SYMBOL pnp 1424 24 R180
SYMATTR InstName Q6
SYMATTR Value 2N3906