* SPICE netlist
V1 N002 0 10
J4 N001 N003 0 J111
R9 N003 PotTreb 100k
R10 N002 N001 100
C4 Vd5 N004 250p
R12 N004 N005 100k
C5 Vs5 N005 100n
R13 Vd5 Vs5 250k
C6 Vs6 N005 47n
R14 Vout2 0 50k
R15 Vs5 Vs6 250k
R16 Vs6 0 10k
C7 Vout2 Vd5 100n
V5 Vin2 0 SINE(0 1 5k) AC 1 0
R17 N004 Vin2 38k
R20 Vg5 N006 5k
R21 Vg6 N007 5k
R22 Vg7 N008 5k
V11 N006 0 PULSE(0 9 1m 10m 0 1) AC 1 0
V8 N007 0 PULSE(0 9 40m 10m 0 1) AC 1 0
V9 N008 0 PULSE(0 9 60m 10m 0 1) AC 1 0
M1 Vd5 Vg5 Vs5 Vs5 BSB012N03LX3
M2 Vs5 Vg6 Vs6 Vs6 BSB012N03LX3
M3 Vs6 Vg7 0 0 BSB012N03LX3
.tran 0 100m 0 1m

* LTspice schematic (.asc)
Version 4
SHEET 1 992 1728
WIRE -240 -848 -304 -848
WIRE -96 -848 -160 -848
WIRE -304 -768 -304 -848
WIRE -96 -768 -96 -848
WIRE -352 -704 -416 -704
WIRE -304 -592 -304 -672
WIRE -144 -592 -304 -592
WIRE -96 -592 -96 -688
WIRE -96 -592 -144 -592
WIRE -368 -256 -416 -256
WIRE -320 -256 -368 -256
WIRE -128 -256 -240 -256
WIRE -16 -256 -128 -256
WIRE 128 -256 48 -256
WIRE -128 -208 -128 -256
WIRE -416 -192 -416 -256
WIRE 128 -160 128 -256
WIRE 192 -160 128 -160
WIRE 240 -160 192 -160
WIRE 336 -160 240 -160
WIRE 448 -160 400 -160
WIRE 496 -160 448 -160
WIRE 128 -144 128 -160
WIRE 240 -144 240 -160
WIRE 16 -64 -16 -64
WIRE 80 -64 16 -64
WIRE 128 -32 128 -48
WIRE 208 -32 128 -32
WIRE 240 -32 240 -64
WIRE 240 -32 208 -32
WIRE -128 16 -128 -128
WIRE -16 16 -128 16
WIRE 128 16 128 -32
WIRE 128 16 48 16
WIRE -400 48 -432 48
WIRE -288 48 -320 48
WIRE -432 112 -432 48
WIRE 128 128 128 16
WIRE 240 128 128 128
WIRE 128 176 128 128
WIRE 240 192 240 128
WIRE -432 240 -432 192
WIRE 32 256 -16 256
WIRE 80 256 32 256
WIRE 448 272 448 -160
WIRE -128 320 -128 16
WIRE -16 320 -128 320
WIRE 128 320 128 272
WIRE 128 320 48 320
WIRE 176 320 128 320
WIRE 240 320 240 272
WIRE 240 320 176 320
WIRE -400 352 -432 352
WIRE -288 352 -320 352
WIRE -432 416 -432 352
WIRE 128 464 128 320
WIRE 240 464 240 320
WIRE -432 544 -432 496
WIRE 32 544 -16 544
WIRE 80 544 32 544
WIRE 128 624 128 560
WIRE 208 624 128 624
WIRE 240 624 240 544
WIRE 240 624 208 624
WIRE -400 672 -432 672
WIRE -288 672 -320 672
WIRE -432 736 -432 672
WIRE 128 736 128 624
WIRE 304 736 128 736
WIRE 448 736 448 352
WIRE 448 736 304 736
WIRE 304 768 304 736
WIRE -432 864 -432 816
FLAG -496 -704 PotTreb
FLAG -144 -592 0
FLAG 304 768 0
FLAG 208 -32 Vs5
FLAG 176 320 Vs6
FLAG 208 624 Vs7
FLAG 192 -160 Vd5
FLAG 16 -64 Vg5
FLAG 32 256 Vg6
FLAG 32 544 Vg7
FLAG -416 -112 0
FLAG 496 -160 Vout2
FLAG -368 -256 Vin2
FLAG -432 240 0
FLAG -288 48 Vg5
FLAG -432 544 0
FLAG -288 352 Vg6
FLAG -432 864 0
FLAG -288 672 Vg7
SYMBOL voltage -96 -784 R0
SYMATTR InstName V1
SYMATTR Value 10
SYMBOL njf -352 -768 R0
SYMATTR InstName J4
SYMATTR Value J111
SYMBOL res -400 -720 R90
SYMATTR InstName R9
SYMATTR Value 100k
SYMBOL res -144 -864 R90
SYMATTR InstName R10
SYMATTR Value 100
SYMBOL cap 48 -272 R90
SYMATTR InstName C4
SYMATTR Value 250p
SYMBOL res -144 -224 R0
SYMATTR InstName R12
SYMATTR Value 100k
SYMBOL cap 48 0 R90
SYMATTR InstName C5
SYMATTR Value 100n
SYMBOL res 224 -160 R0
SYMATTR InstName R13
SYMATTR Value 250k
SYMBOL cap 48 304 R90
SYMATTR InstName C6
SYMATTR Value 47n
SYMBOL res 432 256 R0
SYMATTR InstName R14
SYMATTR Value 50k
SYMBOL res 224 176 R0
SYMATTR InstName R15
SYMATTR Value 250k
SYMBOL res 224 448 R0
SYMATTR InstName R16
SYMATTR Value 10k
SYMBOL cap 400 -176 R90
SYMATTR InstName C7
SYMATTR Value 100n
SYMBOL Misc\\signal -416 -208 R0
SYMATTR Value2 AC 1 0
SYMATTR InstName V5
SYMATTR Value SINE(0 1 5k)
SYMBOL res -224 -272 R90
SYMATTR InstName R17
SYMATTR Value 38k
SYMBOL res -304 32 R90
SYMATTR InstName R20
SYMATTR Value 5k
SYMBOL res -304 336 R90
SYMATTR InstName R21
SYMATTR Value 5k
SYMBOL res -304 656 R90
SYMATTR InstName R22
SYMATTR Value 5k
SYMBOL Misc\\signal -432 96 R0
SYMATTR Value2 AC 1 0
SYMATTR InstName V11
SYMATTR Value PULSE(0 9 1m 10m 0 1)
SYMBOL Misc\\signal -432 400 R0
SYMATTR Value2 AC 1 0
SYMATTR InstName V8
SYMATTR Value PULSE(0 9 40m 10m 0 1)
SYMBOL Misc\\signal -432 720 R0
SYMATTR Value2 AC 1 0
SYMATTR InstName V9
SYMATTR Value PULSE(0 9 60m 10m 0 1)
SYMBOL nmos 80 -144 R0
SYMATTR InstName M1
SYMATTR Value BSB012N03LX3
SYMBOL nmos 80 176 R0
SYMATTR InstName M2
SYMATTR Value BSB012N03LX3
SYMBOL nmos 80 464 R0
SYMATTR InstName M3
SYMATTR Value BSB012N03LX3