* SPICE netlist
R4 N001 N010 1110K
R3 N010 N011 33.2K
R2 N011 N012 29.4K
R1 N012 0 37.4K
R8 N004 N013 2206K
R7 N013 N014 66.5K
R6 N014 N016 100K
R5 N016 0 33.2K
M1 N001 N007 N002 N002 PSMN4R8100BSE
Rsense_1 N003 OUT 1.2m
Rsense_2 N006 OUT 1.2m
C_qual N017 0 2.20n
C_tmr1 N018 0 33n
C_tmr2 N019 0 33n
C_IntVcc N015 0 1
C_EXTVcc OUT 0 .1
C_CPO OUT N009 1
CSN1 N004 0 10 Rser=1.15
Lsource_1 Primary_Supply N001 10n Rser=10m
Lsource_2 Secondary_Supply N004 10n Rser=10m
CGS1 N002 N007 47n
CGS2 N005 N008 47n
VSecondary_Supply Secondary_Supply 0 24V
VPrimary_Supply Primary_Supply 0 PWL(0 12 1 12 +10m 0)
XU1 N009 OUT OUT N003 N002 N007 N001 N010 N011 N012 N018 N015 NC_01 NC_02 NC_03 N015 N015 NC_04 N017 0 N015 NC_05 NC_06 NC_07 N015 N019 N016 N014 N013 N004 N008 N005 N006 OUT 0 OUT LTC4421 ;pnba CPO)CPORef)Out1)Sense1)Source1)Gate1)V1)UVF1)UVR1)OV1)Tmr1)_DISABLE1)_CH1)_VALID1)_FAULT1)CASIN)IntVcc)CASOUT)Qual)RETRY)_SHDN)_FAULT2)_VALID2)_CH2)_DISABLE2)Tmr2)OV2)UVR2)UVF2)V2)Gate2)Source2)Sense2)Out2)Gnd)ExtVcc
M2 N004 N008 N005 N005 PSMN4R8100BSE
M3 N003 N007 N002 N002 PSMN4R8100BSE
M4 N006 N008 N005 N005 PSMN4R8100BSE
Rload OUT 0 2
Cload OUT 0 400
CSN3 N001 0 10 Rser=.58
.tran 2

* LTspice schematic (.asc)
Version 4
SHEET 1 2928 1392
WIRE -1416 -696 -1464 -696
WIRE -952 -696 -1416 -696
WIRE -696 -696 -872 -696
WIRE -584 -696 -696 -696
WIRE -248 -696 -584 -696
WIRE -232 -696 -248 -696
WIRE -56 -696 -136 -696
WIRE -24 -696 -56 -696
WIRE 120 -696 72 -696
WIRE 232 -696 200 -696
WIRE 280 -696 232 -696
WIRE 1080 -696 280 -696
WIRE 1128 -696 1080 -696
WIRE 1240 -696 1128 -696
WIRE 1464 -696 1240 -696
WIRE -584 -680 -584 -696
WIRE -1416 -664 -1416 -696
WIRE 1240 -664 1240 -696
WIRE 1464 -664 1464 -696
WIRE -584 -600 -584 -616
WIRE 1240 -568 1240 -600
WIRE 1464 -568 1464 -584
WIRE -1416 -552 -1416 -584
WIRE -1416 -504 -1464 -504
WIRE -968 -504 -1416 -504
WIRE -664 -504 -888 -504
WIRE -520 -504 -664 -504
WIRE 488 -504 -520 -504
WIRE 504 -504 488 -504
WIRE 680 -504 600 -504
WIRE 696 -504 680 -504
WIRE 808 -504 792 -504
WIRE 856 -504 808 -504
WIRE 968 -504 936 -504
WIRE 1080 -504 1080 -696
WIRE 1080 -504 968 -504
WIRE -664 -488 -664 -504
WIRE -1416 -472 -1416 -504
WIRE -152 -424 -152 -648
WIRE -136 -424 -152 -424
WIRE -56 -424 -56 -696
WIRE -56 -424 -72 -424
WIRE -664 -392 -664 -424
WIRE 280 -360 280 -696
WIRE 376 -360 280 -360
WIRE 584 -360 584 -456
WIRE 600 -360 584 -360
WIRE 680 -360 680 -504
WIRE 680 -360 664 -360
WIRE -1416 -344 -1416 -392
WIRE -152 -344 -152 -424
WIRE -8 -344 -8 -648
WIRE -8 -344 -152 -344
WIRE 280 -328 280 -360
WIRE 232 -296 232 -696
WIRE 232 -296 168 -296
WIRE 968 -280 968 -504
WIRE 968 -280 904 -280
WIRE -696 -264 -696 -696
WIRE 584 -264 584 -360
WIRE 712 -264 712 -456
WIRE 712 -264 584 -264
WIRE -248 -232 -248 -696
WIRE -152 -232 -152 -344
WIRE -56 -232 -56 -424
WIRE 72 -232 72 -696
WIRE 168 -232 168 -296
WIRE 280 -232 280 -264
WIRE 376 -232 376 -360
WIRE 488 -232 488 -504
WIRE 584 -232 584 -264
WIRE 680 -232 680 -360
WIRE 808 -232 808 -504
WIRE 904 -232 904 -280
WIRE -696 -168 -696 -184
WIRE -376 -168 -696 -168
WIRE -696 -152 -696 -168
WIRE 1128 -136 1128 -696
WIRE 1128 -136 1032 -136
WIRE 1128 -120 1128 -136
WIRE -696 -40 -696 -72
WIRE -376 -40 -696 -40
WIRE -696 -24 -696 -40
WIRE 1128 -24 1128 -56
WIRE -696 88 -696 56
WIRE -376 88 -696 88
WIRE -696 104 -696 88
WIRE -520 120 -520 -504
WIRE -696 200 -696 184
WIRE -520 216 -520 200
WIRE -376 216 -520 216
WIRE -520 232 -520 216
WIRE 1064 328 1032 328
WIRE -520 344 -520 312
WIRE -376 344 -520 344
WIRE -520 360 -520 344
WIRE 1064 376 1032 376
WIRE 1064 424 1064 376
WIRE 1064 424 1032 424
WIRE -520 472 -520 440
WIRE -376 472 -520 472
WIRE 1064 472 1064 424
WIRE 1064 472 1032 472
WIRE -520 488 -520 472
WIRE 1064 520 1064 472
WIRE 1064 520 1032 520
WIRE -520 584 -520 568
WIRE -24 584 -24 568
WIRE 680 584 680 568
WIRE 1064 584 1064 520
WIRE 1064 584 680 584
WIRE 152 616 152 568
WIRE 328 616 328 568
WIRE 504 616 504 568
WIRE 680 616 680 584
WIRE 152 696 152 680
WIRE 328 696 328 680
WIRE 504 696 504 680
WIRE 680 696 680 680
FLAG -520 584 0
FLAG 1240 -568 0
FLAG -24 584 0
FLAG 1128 -24 0
FLAG -584 -600 0
FLAG -664 -392 0
FLAG -1464 -696 Primary_Supply
FLAG -1464 -504 Secondary_Supply
FLAG -1416 -344 0
FLAG -1416 -552 0
FLAG 1464 -696 OUT
FLAG 1064 328 0
FLAG 152 696 0
FLAG 328 696 0
FLAG 504 696 0
FLAG 680 696 0
FLAG -696 200 0
FLAG 1464 -568 0
SYMBOL res -712 -280 R0
SYMATTR Value 1110K
SYMATTR InstName R4
SYMBOL res -712 -168 R0
SYMATTR Value 33.2K
SYMATTR InstName R3
SYMBOL res -712 -40 R0
SYMATTR Value 29.4K
SYMATTR InstName R2
SYMBOL res -712 88 R0
SYMATTR Value 37.4K
SYMATTR InstName R1
SYMBOL res -536 104 R0
SYMATTR Value 2206K
SYMATTR InstName R8
SYMBOL res -536 216 R0
SYMATTR Value 66.5K
SYMATTR InstName R7
SYMBOL res -536 344 R0
SYMATTR Value 100K
SYMATTR InstName R6
SYMBOL res -536 472 R0
SYMATTR Value 33.2K
SYMATTR InstName R5
SYMBOL nmos -232 -648 R270
SYMATTR InstName M1
SYMATTR Value PSMN4R8100BSE
SYMBOL res 104 -680 R270
SYMATTR InstName Rsense_1
SYMATTR Value 1.2m
SYMBOL res 840 -488 R270
SYMATTR InstName Rsense_2
SYMATTR Value 1.2m
SYMBOL cap 136 616 R0
SYMATTR Value 2.20n
SYMATTR InstName C_qual
SYMBOL cap 312 616 R0
SYMATTR Value 33n
SYMATTR InstName C_tmr1
SYMBOL cap 488 616 R0
SYMATTR Value 33n
SYMATTR InstName C_tmr2
SYMBOL cap 664 616 R0
SYMATTR Value 1
SYMATTR InstName C_IntVcc
SYMBOL cap 1112 -120 R0
SYMATTR Value .1
SYMATTR InstName C_EXTVcc
SYMBOL cap 264 -328 R0
SYMATTR Value 1
SYMATTR InstName C_CPO
SYMBOL cap -680 -488 R0
SYMATTR Value 10
SYMATTR Value2 Rser=1.15
SYMATTR InstName CSN1
SYMBOL ind -968 -680 R270
SYMATTR InstName Lsource_1
SYMATTR Value 10n
SYMATTR Value2 Rser=10m
SYMBOL ind -984 -488 R270
SYMATTR InstName Lsource_2
SYMATTR Value 10n
SYMATTR Value2 Rser=10m
SYMBOL cap -72 -440 R90
SYMATTR InstName CGS1
SYMATTR Value 47n
SYMBOL cap 664 -376 R90
SYMATTR InstName CGS2
SYMATTR Value 47n
SYMBOL VOLTAGE -1416 -488 R0
SYMATTR InstName Secondary_Supply
SYMATTR Value 24V
SYMBOL VOLTAGE -1416 -680 R0
SYMATTR InstName Primary_Supply
SYMATTR Value PWL(0 12 1 12 +10m 0)
SYMBOL LTC4421 328 168 R0
SYMATTR InstName U1
SYMBOL nmos 504 -456 R270
SYMATTR InstName M2
SYMATTR Value PSMN4R8100BSE
SYMBOL nmos 72 -648 M270
SYMATTR InstName M3
SYMATTR Value PSMN4R8100BSE
SYMBOL nmos 792 -456 M270
SYMATTR InstName M4
SYMATTR Value PSMN4R8100BSE
SYMBOL res 1448 -680 R0
SYMATTR InstName Rload
SYMATTR Value 2
SYMBOL cap 1224 -664 R0
SYMATTR InstName Cload
SYMATTR Value 400
SYMBOL cap -600 -680 R0
SYMATTR Value 10
SYMATTR Value2 Rser=.58
SYMATTR InstName CSN3