* SPICE netlist
R1 N001 N002 7m
MQ1 N002 N004 N003 N003 IRF7413
R2 N004 N009 10
R3 N010 N009 100
MQ2 N006 N008 N007 N007 IRF7413
R4 N008 N009 10
R5 N005 N006 5m
C1 N010 0 0.047
V1 N001 0 PULSE(0 5 5m 5m 5m 250m 300m)
V2 N005 0 PULSE(0 3.3 5m 5m 5m 250m 300m)
V3 N012 0 PULSE(0 12 5m 5m 5m 400m 450m)
V4 N014 0 PULSE(0 -12 5m 5m 5m 400m 450m)
V5 N015 0 PWL(0 0 40m 0 +1u 3.3)
V6 N019 0 12
R6 N017 N019 10K
C2 N007 0 30
C3 N011 0 10
C4 N013 0 10
C5 N016 0 0.1
C6 N003 0 30
R7 N018 N019 10K
XU1 N012 N014 N007 N016 N015 N017 N018 0 N005 N006 N009 N002 N001 N003 N013 N011 LTC1643AH ;pnba 12Vin)VeeIN)3Vout)Timer)ON)_Fault)_PWRGD)GND)3Vin)3Vsense)Gate)5Vsense)5Vin)5Vout)VeeOUT)12Vout
Rload1 N003 0 2
Rload2 N007 0 0.87
Rload3 N011 0 30
Rload4 N013 0 150
.tran 550m

* LTspice schematic (.asc)
Version 4
SHEET 1 1664 1040
WIRE 160 -520 -768 -520
WIRE 176 -520 160 -520
WIRE 272 -520 256 -520
WIRE 336 -520 272 -520
WIRE 640 -520 432 -520
WIRE 704 -520 640 -520
WIRE 832 -520 704 -520
WIRE -768 -504 -768 -520
WIRE 704 -504 704 -520
WIRE 832 -504 832 -520
WIRE 416 -424 416 -472
WIRE -768 -408 -768 -424
WIRE 704 -408 704 -440
WIRE 832 -408 832 -424
WIRE -288 -328 -768 -328
WIRE -272 -328 -288 -328
WIRE -176 -328 -192 -328
WIRE -144 -328 -176 -328
WIRE 48 -328 -48 -328
WIRE 704 -328 48 -328
WIRE 832 -328 704 -328
WIRE -768 -312 -768 -328
WIRE 704 -312 704 -328
WIRE 832 -312 832 -328
WIRE -64 -232 -64 -280
WIRE -768 -216 -768 -232
WIRE 704 -216 704 -248
WIRE 832 -216 832 -232
WIRE -64 -136 -64 -152
WIRE 416 -136 416 -344
WIRE 416 -136 -64 -136
WIRE 432 -136 416 -136
WIRE 528 -136 512 -136
WIRE 608 -136 592 -136
WIRE 640 -72 640 -520
WIRE 640 -72 400 -72
WIRE -288 -56 -288 -328
WIRE -176 -56 -176 -328
WIRE -64 -56 -64 -136
WIRE 48 -56 48 -328
WIRE 160 -56 160 -520
WIRE 272 -56 272 -520
WIRE 400 -56 400 -72
WIRE -368 40 -400 40
WIRE 704 40 480 40
WIRE 832 40 704 40
WIRE 704 56 704 40
WIRE 832 56 832 40
WIRE -816 104 -832 104
WIRE -368 104 -736 104
WIRE 608 152 480 152
WIRE 704 152 704 120
WIRE 832 152 832 136
WIRE -368 168 -576 168
WIRE -816 232 -832 232
WIRE -576 232 -576 168
WIRE -576 232 -736 232
WIRE -368 232 -528 232
WIRE 608 248 608 152
WIRE 704 248 608 248
WIRE 832 248 704 248
WIRE 496 264 480 264
WIRE 576 264 560 264
WIRE 704 264 704 248
WIRE 832 264 832 248
WIRE -368 296 -480 296
WIRE -480 344 -480 296
WIRE -736 360 -752 360
WIRE -528 360 -528 232
WIRE -528 360 -656 360
WIRE -368 360 -400 360
WIRE 704 360 704 328
WIRE 832 360 832 344
WIRE -400 424 -400 360
WIRE -640 520 -672 520
WIRE -480 520 -480 424
WIRE -480 520 -560 520
WIRE -400 520 -400 504
WIRE -400 520 -480 520
FLAG 704 -408 0
FLAG 832 -408 0
FLAG 608 -136 0
FLAG -752 360 0
FLAG -768 -408 0
FLAG 704 -216 0
FLAG 832 -216 0
FLAG -768 -216 0
FLAG -832 104 0
FLAG -832 232 0
FLAG -672 520 0
FLAG 704 152 0
FLAG 832 152 0
FLAG 704 360 0
FLAG 832 360 0
FLAG 576 264 0
FLAG -400 40 0
SYMBOL res 160 -504 R270
SYMATTR InstName R1
SYMATTR Value 7m
SYMBOL nmos 336 -472 R270
SYMATTR InstName Q1
SYMATTR Value IRF7413
SYMBOL res 400 -440 R0
SYMATTR InstName R2
SYMATTR Value 10
SYMBOL res 528 -152 R90
SYMATTR InstName R3
SYMATTR Value 100
SYMBOL nmos -144 -280 R270
SYMATTR InstName Q2
SYMATTR Value IRF7413
SYMBOL res -80 -248 R0
SYMATTR InstName R4
SYMATTR Value 10
SYMBOL res -288 -312 R270
SYMATTR InstName R5
SYMATTR Value 5m
SYMBOL cap 528 -120 R270
SYMATTR InstName C1
SYMATTR Value 0.047
SYMBOL voltage -768 -520 R0
SYMATTR InstName V1
SYMATTR Value PULSE(0 5 5m 5m 5m 250m 300m)
SYMBOL voltage -768 -328 R0
SYMATTR InstName V2
SYMATTR Value PULSE(0 3.3 5m 5m 5m 250m 300m)
SYMBOL voltage -720 104 R90
SYMATTR InstName V3
SYMATTR Value PULSE(0 12 5m 5m 5m 400m 450m)
SYMBOL voltage -720 232 R90
SYMATTR InstName V4
SYMATTR Value PULSE(0 -12 5m 5m 5m 400m 450m)
SYMBOL voltage -640 360 R90
SYMATTR InstName V5
SYMATTR Value PWL(0 0 40m 0 +1u 3.3)
SYMBOL voltage -544 520 R90
SYMATTR InstName V6
SYMATTR Value 12
SYMBOL res -496 328 R0
SYMATTR InstName R6
SYMATTR Value 10K
SYMBOL cap 688 -312 R0
SYMATTR InstName C2
SYMATTR Value 30
SYMBOL cap 688 56 R0
SYMATTR InstName C3
SYMATTR Value 10
SYMBOL cap 688 264 R0
SYMATTR InstName C4
SYMATTR Value 10
SYMBOL cap 496 280 R270
SYMATTR InstName C5
SYMATTR Value 0.1
SYMBOL cap 688 -504 R0
SYMATTR InstName C6
SYMATTR Value 30
SYMBOL res -416 408 R0
SYMATTR InstName R7
SYMATTR Value 10K
SYMBOL LTC1643AH 48 168 R0
SYMATTR InstName U1
SYMBOL res 816 -520 R0
SYMATTR InstName Rload1
SYMATTR Value 2
SYMBOL res 816 -328 R0
SYMATTR InstName Rload2
SYMATTR Value 0.87
SYMBOL res 816 40 R0
SYMATTR InstName Rload3
SYMATTR Value 30
SYMBOL res 816 248 R0
SYMATTR InstName Rload4
SYMATTR Value 150