* SPICE netlist
Q1 N005 N004 N002 0 PNP
Q2 N004 N004 N003 0 PNP
Q3 N007 N005 N004 0 PNP
Q4 N009 N006 N007 0 PNP
Q5 N008 N006 N005 0 PNP
R1 N009 N011 1k
R2 N008 N010 1k
R3 N001 N002 200
R4 N001 N003 200
R5 N001 N006 8k
R6 N006 0 1.6k
M1 N010 N012 N013 N013 NMOS
M2 N011 0 N015 N015 NMOS
M3 N014 N016 N017 N017 NMOS
R9 N014 N013 500
R10 N015 N014 500
R11 0 N017 1k
R12 0 N017 1k
R13 0 N016 3k
M4 N016 N016 N017 N017 NMOS
R14 0 0 1Meg
R15 0 0 1Meg
R16 N012 0 1Meg
V1 N001 0 15
C1 N007 0 820p
V2 N012 0 PWL(0 -2 30m -2 30.001m 2)
R17 N016 N018 2.5k
R18 N018 0 1k
.tran 0 5us 0 1e-15

* LTspice schematic (.asc)
Version 4
SHEET 1 976 1744
WIRE -24 -824 -24 -872
WIRE -168 -712 -296 -712
WIRE -24 -712 -24 -744
WIRE -24 -712 -168 -712
WIRE 104 -712 -24 -712
WIRE -296 -664 -296 -712
WIRE -168 -648 -168 -712
WIRE 104 -632 104 -712
WIRE -168 -488 -168 -568
WIRE 104 -488 104 -552
WIRE -24 -440 -104 -440
WIRE 40 -440 -24 -440
WIRE -24 -360 -24 -440
WIRE 104 -360 104 -392
WIRE 104 -360 -24 -360
WIRE 104 -296 104 -360
WIRE -168 -248 -168 -392
WIRE 40 -248 -168 -248
WIRE -296 -184 -296 -584
WIRE -24 -184 -296 -184
WIRE 104 -168 104 -200
WIRE 264 -168 104 -168
WIRE -168 -120 -168 -248
WIRE 104 -120 104 -168
WIRE -296 -104 -296 -184
WIRE 264 -104 264 -168
WIRE -24 -72 -24 -184
WIRE -24 -72 -104 -72
WIRE 40 -72 -24 -72
WIRE 264 8 264 -40
WIRE -296 24 -296 -24
WIRE -168 40 -168 -24
WIRE 104 40 104 -24
WIRE -168 152 -168 120
WIRE 104 152 104 120
WIRE -296 232 -408 232
WIRE -216 232 -296 232
WIRE 248 232 152 232
WIRE 376 232 248 232
WIRE 488 232 376 232
WIRE -408 280 -408 232
WIRE -296 280 -296 232
WIRE 248 280 248 232
WIRE 376 280 376 232
WIRE -168 328 -168 248
WIRE -152 328 -168 328
WIRE -24 328 -72 328
WIRE 8 328 -24 328
WIRE 104 328 104 248
WIRE 104 328 88 328
WIRE 488 328 488 232
WIRE -408 408 -408 360
WIRE -296 408 -296 360
WIRE 248 408 248 360
WIRE 312 408 248 408
WIRE 376 408 376 360
WIRE 376 408 312 408
WIRE 312 456 312 408
WIRE -24 520 -24 328
WIRE -344 536 -472 536
WIRE -472 600 -472 536
WIRE -344 600 -344 536
WIRE -232 600 -344 600
WIRE -72 600 -232 600
WIRE -232 632 -232 600
WIRE -344 680 -344 600
WIRE -312 680 -344 680
WIRE -168 680 -216 680
WIRE -24 680 -24 616
WIRE -24 680 -168 680
WIRE -472 728 -472 680
WIRE -344 728 -344 680
WIRE -168 728 -168 680
WIRE -24 728 -24 680
WIRE -472 872 -472 808
WIRE -344 872 -344 808
WIRE -168 872 -168 808
WIRE -24 872 -24 808
FLAG -296 24 0
FLAG -296 408 0
FLAG 312 456 0
FLAG -24 872 0
FLAG -168 872 0
FLAG -344 872 0
FLAG -24 -872 0
FLAG 264 8 0
FLAG 488 328 0
FLAG -408 408 0
FLAG -472 872 0
SYMBOL pnp -104 -392 R180
SYMATTR InstName Q1
SYMBOL pnp 40 -392 M180
SYMATTR InstName Q2
SYMBOL pnp 40 -200 M180
SYMATTR InstName Q3
SYMBOL pnp 40 -24 M180
SYMATTR InstName Q4
SYMBOL pnp -104 -24 R180
SYMATTR InstName Q5
SYMBOL res 88 24 R0
SYMATTR InstName R1
SYMATTR Value 1k
SYMBOL res -184 24 R0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL res -184 -664 R0
SYMATTR InstName R3
SYMATTR Value 200
SYMBOL res 88 -648 R0
SYMATTR InstName R4
SYMATTR Value 200
SYMBOL res -312 -680 R0
SYMATTR InstName R5
SYMATTR Value 8k
SYMBOL res -312 -120 R0
SYMATTR InstName R6
SYMATTR Value 1.6k
SYMBOL nmos -216 152 R0
SYMATTR InstName M1
SYMBOL nmos 152 152 M0
SYMATTR InstName M2
SYMBOL nmos -72 520 R0
SYMATTR InstName M3
SYMBOL res -56 312 R90
SYMATTR InstName R9
SYMATTR Value 500
SYMBOL res 104 312 R90
SYMATTR InstName R10
SYMATTR Value 500
SYMBOL res -8 824 R180
SYMATTR InstName R11
SYMATTR Value 1k
SYMBOL res -152 824 R180
SYMATTR InstName R12
SYMATTR Value 1k
SYMBOL res -328 824 R180
SYMATTR InstName R13
SYMATTR Value 3k
SYMBOL nmos -312 632 M90
SYMATTR InstName M4
SYMBOL res 232 264 R0
SYMATTR InstName R14
SYMATTR Value 1Meg
SYMBOL res 360 264 R0
SYMATTR InstName R15
SYMATTR Value 1Meg
SYMBOL res -312 264 R0
SYMATTR InstName R16
SYMATTR Value 1Meg
SYMBOL voltage -24 -728 R180
SYMATTR InstName V1
SYMATTR Value 15
SYMBOL cap 248 -104 R0
SYMATTR InstName C1
SYMATTR Value 820p
SYMBOL voltage -408 264 R0
SYMATTR InstName V2
SYMATTR Value PWL(0 -2 30m -2 30.001m 2)
SYMBOL res -488 584 R0
SYMATTR InstName R17
SYMATTR Value 2.5k
SYMBOL res -488 712 R0
SYMATTR InstName R18
SYMATTR Value 1k