* SPICE netlist
R1 N010 VIN 10
C4 N019 0 10n
R2 VIN N001 0.5m
R4 N006 N009 10
R22 N001 N003 10
R21 VIN N002 10
C5 N021 0 10n
R9 N015 N019 100k
R10 N019 0 11.5k
R24 VOUT N014 51.1k
R16 VIN N016 10K
R7 VIN N013 51.1k
R8 N013 0 3.01k
R13 N015 N017 100k
R14 N017 0 51.1k
R11 N015 N018 100k
R12 N018 0 4.99k
C7 0 N009 22n
C2 N013 0 10n
V4 VIN 0 PWL(0 0.01 50m 12 180m 12 250m 0)
R26 N002 N007 100
R27 N003 N008 100
C9 N008 N007 100n
C8 N007 0 100n
C10 0 N008 100n
R15 N020 VIN 100K
Rload VOUT 0 1k
M3 N001 N004 VOUT VOUT PSMN0R925YLC Tambient=55 RthetaJA=35 Cheatsink=0 Imult=9.43E+1 Iexponent=1.00E-3 C6=1.64E-4 R6=4.40E-3 C5=8.20E-4 R5=2.20E-2 C4=3.30E-3 R4=1.10E-1 C3=1.00E-1 R3=2.70E-1 C2=1.55E-1 R2=0.1m C1=0 R1=0.1m
R18 N005 N009 10
R19 N004 N009 10
R20 VIN N002 10
R23 N001 N003 10
R6 N011 0 6.04k
R5 VIN N011 51.1k
C1 N011 0 100n
C6 N010 0 1
C3 N015 0 1
R17 VOUT N012 1k
Cload VOUT 0 1000
R25 N014 0 4.99k
R3 VIN N001 0.5m
M1 N001 N006 VOUT VOUT PSMN0R925YLC Tambient=55 RthetaJA=35 Cheatsink=0 Imult=9.43E+1 Iexponent=1.00E-3 C6=1.64E-4 R6=4.40E-3 C5=8.20E-4 R5=2.20E-2 C4=3.30E-3 R4=1.10E-1 C3=1.00E-1 R3=2.70E-1 C2=1.55E-1 R2=0.1m C1=0 R1=0.1m
M2 N001 N005 VOUT VOUT PSMN0R925YLC Tambient=55 RthetaJA=35 Cheatsink=0 Imult=9.43E+1 Iexponent=1.00E-3 C6=1.64E-4 R6=4.40E-3 C5=8.20E-4 R5=2.20E-2 C4=3.30E-3 R4=1.10E-1 C3=1.00E-1 R3=2.70E-1 C2=1.55E-1 R2=0.1m C1=0 R1=0.1m
XU1 NC_01 NC_02 N002 N003 N017 N018 N007 N008 N013 N019 N014 N011 N010 N020 NC_03 N009 0 0 N016 N021 N015 N012 ADM1281-3 oc_filt_select=1 oc_trip_select=1 fhdis=0 oc_retry_dis=0 ;pnba _RETRY)EN)HS+)HS-)Iset)Istart)MO+)MO-)OV)Pset)PWGin)UV)Vcc)_FAULT)CSout)GATE)GND)PGND)PWRGD)TIMER)Vcap)Vout
.tran 250m startup

* LTspice schematic (.asc)
Version 4.1
SHEET 1 2496 1216
WIRE 480 -608 432 -608
WIRE 912 -608 576 -608
WIRE 432 -512 432 -608
WIRE 624 -512 432 -512
WIRE 912 -512 912 -608
WIRE 912 -512 720 -512
WIRE 160 -496 0 -496
WIRE 384 -496 240 -496
WIRE -1200 -400 -1248 -400
WIRE -784 -400 -1200 -400
WIRE -608 -400 -784 -400
WIRE -144 -400 -608 -400
WIRE 0 -400 0 -496
WIRE 0 -400 -144 -400
WIRE 112 -400 0 -400
WIRE 160 -400 112 -400
WIRE 272 -400 240 -400
WIRE 384 -400 384 -496
WIRE 384 -400 272 -400
WIRE 432 -400 432 -512
WIRE 432 -400 384 -400
WIRE 768 -400 432 -400
WIRE 912 -400 912 -512
WIRE 912 -400 864 -400
WIRE 1024 -400 912 -400
WIRE 1120 -400 1024 -400
WIRE 1200 -400 1120 -400
WIRE 1248 -400 1200 -400
WIRE -1248 -368 -1248 -400
WIRE 0 -368 0 -400
WIRE 112 -368 112 -400
WIRE 272 -368 272 -400
WIRE 384 -368 384 -400
WIRE 1120 -368 1120 -400
WIRE 1248 -368 1248 -400
WIRE 0 -272 0 -288
WIRE 112 -272 112 -288
WIRE 112 -272 0 -272
WIRE 144 -272 112 -272
WIRE 272 -272 272 -288
WIRE 272 -272 240 -272
WIRE 384 -272 384 -288
WIRE 384 -272 272 -272
WIRE -1248 -256 -1248 -288
WIRE 1120 -256 1120 -288
WIRE 1248 -256 1248 -304
WIRE 144 -240 144 -272
WIRE 240 -240 240 -272
WIRE 560 -192 560 -560
WIRE 704 -192 704 -464
WIRE -144 -176 -144 -400
WIRE 848 -176 848 -352
WIRE 64 -112 48 -112
WIRE 144 -112 144 -160
WIRE 144 -112 128 -112
WIRE 160 -112 144 -112
WIRE 240 -112 240 -160
WIRE 240 -112 224 -112
WIRE 256 -112 240 -112
WIRE 336 -112 320 -112
WIRE 0 -64 0 -272
WIRE 64 -64 0 -64
WIRE 384 -64 384 -272
WIRE 384 -64 320 -64
WIRE 560 -64 560 -112
WIRE 560 -64 432 -64
WIRE 704 -64 704 -112
WIRE 704 -64 560 -64
WIRE 848 -64 848 -96
WIRE 848 -64 704 -64
WIRE -784 -32 -784 -400
WIRE -608 -32 -608 -400
WIRE 64 -32 64 -64
WIRE 144 -32 144 -112
WIRE 240 -32 240 -112
WIRE 320 -32 320 -64
WIRE 1024 -16 1024 -400
WIRE -272 32 -336 32
WIRE -144 32 -144 -96
WIRE -144 32 -208 32
WIRE -16 32 -144 32
WIRE 432 32 432 -64
WIRE 432 32 400 32
WIRE 464 32 432 32
WIRE 544 32 528 32
WIRE -784 96 -784 48
WIRE -784 96 -880 96
WIRE -16 96 -784 96
WIRE 704 96 400 96
WIRE 912 96 912 -400
WIRE 912 96 784 96
WIRE -784 144 -784 96
WIRE -880 160 -880 96
WIRE -608 160 -608 48
WIRE -608 160 -688 160
WIRE -16 160 -608 160
WIRE 1024 160 1024 64
WIRE 1024 160 400 160
WIRE -688 192 -688 160
WIRE -608 208 -608 160
WIRE -416 224 -496 224
WIRE -288 224 -416 224
WIRE -176 224 -288 224
WIRE -16 224 -176 224
WIRE 464 224 400 224
WIRE 624 224 544 224
WIRE 672 224 624 224
WIRE -416 240 -416 224
WIRE -288 240 -288 224
WIRE -176 240 -176 224
WIRE 1024 240 1024 160
WIRE -496 256 -496 224
WIRE -16 288 -80 288
WIRE -880 320 -880 224
WIRE -784 320 -784 224
WIRE -688 320 -688 256
WIRE -608 320 -608 288
WIRE -496 336 -496 320
WIRE -176 336 -176 320
WIRE -80 336 -80 288
WIRE -80 336 -176 336
WIRE -16 352 -48 352
WIRE -288 368 -288 320
WIRE -48 368 -48 352
WIRE -48 368 -288 368
WIRE -416 416 -416 320
WIRE -416 416 -496 416
WIRE -16 416 -416 416
WIRE 480 416 400 416
WIRE 624 416 624 224
WIRE 624 416 560 416
WIRE 1024 416 1024 320
WIRE -416 464 -416 416
WIRE -288 464 -288 368
WIRE -176 464 -176 336
WIRE -496 480 -496 416
WIRE -16 480 -80 480
WIRE -496 576 -496 544
WIRE -416 576 -416 544
WIRE -288 576 -288 544
WIRE -176 576 -176 544
WIRE -80 576 -80 544
WIRE 128 576 128 544
WIRE 240 576 240 544
WIRE 240 576 128 576
WIRE 128 608 128 576
FLAG -496 576 0
FLAG -1200 -400 VIN
FLAG -176 576 0
FLAG -80 576 0
FLAG -416 576 0
FLAG -608 320 0
FLAG -288 576 0
FLAG 544 32 0
FLAG -688 320 0
FLAG -1248 -256 0
FLAG 1200 -400 VOUT
FLAG 672 224 VIN
FLAG 1120 -256 0
FLAG -880 320 0
FLAG -784 320 0
FLAG -336 32 0
FLAG -496 336 0
FLAG 1248 -256 0
FLAG 1024 416 0
FLAG 128 608 0
FLAG 336 -112 0
FLAG 48 -112 0
SYMBOL res -160 -80 M180
SYMATTR InstName R1
SYMATTR Value 10
SYMBOL cap -512 480 R0
SYMATTR InstName C4
SYMATTR Value 10n
SYMBOL res 144 -384 R270
SYMATTR InstName R2
SYMATTR Value 0.5m
SYMBOL res 832 -192 R0
SYMATTR InstName R4
SYMATTR Value 10
SYMBOL res 256 -384 R0
SYMATTR InstName R22
SYMATTR Value 10
SYMBOL res 96 -384 R0
SYMATTR InstName R21
SYMATTR Value 10
SYMBOL cap -96 480 R0
SYMATTR InstName C5
SYMATTR Value 10n
SYMBOL res -432 224 R0
SYMATTR InstName R9
SYMATTR Value 100k
SYMBOL res -432 448 R0
SYMATTR InstName R10
SYMATTR Value 11.5k
SYMBOL res 1008 -32 R0
SYMATTR InstName R24
SYMATTR Value 51.1k
SYMBOL res 560 208 R90
SYMATTR InstName R16
SYMATTR Value 10K
SYMBOL res -624 -48 R0
SYMATTR InstName R7
SYMATTR Value 51.1k
SYMBOL res -624 192 R0
SYMATTR InstName R8
SYMATTR Value 3.01k
SYMBOL res -192 224 R0
SYMATTR InstName R13
SYMATTR Value 100k
SYMBOL res -192 448 R0
SYMATTR Value 51.1k
SYMATTR InstName R14
SYMBOL res -304 224 R0
SYMATTR InstName R11
SYMATTR Value 100k
SYMBOL res -304 448 R0
SYMATTR InstName R12
SYMATTR Value 4.99k
SYMBOL cap 528 16 R90
SYMATTR InstName C7
SYMATTR Value 22n
SYMBOL cap -704 192 R0
SYMATTR InstName C2
SYMATTR Value 10n
SYMBOL voltage -1248 -384 R0
SYMATTR InstName V4
SYMATTR Value PWL(0 0.01 50m 12 180m 12 250m 0)
SYMBOL res 128 -256 R0
SYMATTR InstName R26
SYMATTR Value 100
SYMBOL res 224 -256 R0
SYMATTR InstName R27
SYMATTR Value 100
SYMBOL cap 224 -128 R90
SYMATTR InstName C9
SYMATTR Value 100n
SYMBOL cap 128 -128 R90
SYMATTR InstName C8
SYMATTR Value 100n
SYMBOL cap 320 -128 R90
SYMATTR InstName C10
SYMATTR Value 100n
SYMBOL res 464 432 R270
SYMATTR InstName R15
SYMATTR Value 100K
SYMBOL res 1104 -384 R0
SYMATTR InstName Rload
SYMATTR Value 1k
SYMBOL nmos 480 -560 R270
SYMATTR InstName M3
SYMATTR Value PSMN0R925YLC
SYMATTR Value2 Tambient=55 RthetaJA=35 Cheatsink=0 Imult=9.43E+1 Iexponent=1.00E-3 C6=1.64E-4 R6=4.40E-3 C5=8.20E-4 R5=2.20E-2 C4=3.30E-3 R4=1.10E-1 C3=1.00E-1 R3=2.70E-1 C2=1.55E-1 R2=0.1m C1=0 R1=0.1m
SYMBOL res 688 -208 R0
SYMATTR InstName R18
SYMATTR Value 10
SYMBOL res 544 -208 R0
SYMATTR InstName R19
SYMATTR Value 10
SYMBOL res -16 -384 R0
SYMATTR InstName R20
SYMATTR Value 10
SYMBOL res 368 -384 R0
SYMATTR InstName R23
SYMATTR Value 10
SYMBOL res -800 128 R0
SYMATTR Value 6.04k
SYMATTR InstName R6
SYMBOL res -800 -48 R0
SYMATTR InstName R5
SYMATTR Value 51.1k
SYMBOL cap -896 160 R0
SYMATTR InstName C1
SYMATTR Value 100n
SYMBOL cap -208 16 R90
SYMATTR InstName C6
SYMATTR Value 1
SYMBOL cap -512 256 R0
SYMATTR InstName C3
SYMATTR Value 1
SYMBOL res 800 80 R90
SYMATTR InstName R17
SYMATTR Value 1k
SYMBOL cap 1232 -368 R0
SYMATTR InstName Cload
SYMATTR Value 1000
SYMBOL res 1008 224 R0
SYMATTR InstName R25
SYMATTR Value 4.99k
SYMBOL res 144 -480 R270
SYMATTR InstName R3
SYMATTR Value 0.5m
SYMBOL nmos 768 -352 R270
SYMATTR InstName M1
SYMATTR Value PSMN0R925YLC
SYMATTR Value2 Tambient=55 RthetaJA=35 Cheatsink=0 Imult=9.43E+1 Iexponent=1.00E-3 C6=1.64E-4 R6=4.40E-3 C5=8.20E-4 R5=2.20E-2 C4=3.30E-3 R4=1.10E-1 C3=1.00E-1 R3=2.70E-1 C2=1.55E-1 R2=0.1m C1=0 R1=0.1m
SYMBOL nmos 624 -464 R270
SYMATTR InstName M2
SYMATTR Value PSMN0R925YLC
SYMATTR Value2 Tambient=55 RthetaJA=35 Cheatsink=0 Imult=9.43E+1 Iexponent=1.00E-3 C6=1.64E-4 R6=4.40E-3 C5=8.20E-4 R5=2.20E-2 C4=3.30E-3 R4=1.10E-1 C3=1.00E-1 R3=2.70E-1 C2=1.55E-1 R2=0.1m C1=0 R1=0.1m
SYMBOL ADM1281-3 192 240 R0
SYMATTR InstName U1