* SPICE netlist
R1 5Vin N001 7m
MQ1 N001 N002 5Vout 5Vout IRF7413
R2 N002 N007 10
R3 N008 N007 1K
MQ2 N003 N004 3Vout 3Vout IRF7413
R4 N004 N007 10
R5 3Vin N003 5m
C1 N008 0 0.01
V1 N019 0 5
R6 N014 N019 10K
C2 3Vout 0 30
C3 N015 0 0.1
C4 5Vout 0 30
R7 N016 N019 10K
V2 N011 0 PWL(0 0 10m 0 +1u 3.3)
R8 N019 N012 10K
R9 N010 N009 18
C5 0 N010 4.7n
Q3 N006 N009 N005 0 2N2222
R10 3Vin N006 12
R11 3Vin N009 1K
XU1 N021 N020 5Vout N015 N013 N014 N016 0 N011 N012 N009 N005 5Vin N001 N007 N003 3Vin 3Vout N018 N017 LTC1644 ;pnba 12Vin)VeeIN)5Vout)Timer)_ON)_Fault)_PWRGD)GND)_ResetIN)_ResetOUT)Drive)Precharge)5Vin)5Vsense)Gate)3Vsense)3Vin)3Vout)VeeOUT)12Vout
R12 N017 0 30
C6 N017 0 10
R13 N018 0 150
C7 N018 0 10
V3 N013 0 PWL(0 3.3 40m 3.3 +1u 0)
V4 N020 0 PULSE(0 -12 5m 5m 5m 400m 450m)
V5 N021 0 PULSE(0 12 5m 5m 5m 400m 450m)
V6 5Vin 0 PULSE(0 5 5m 5m 5m 250m 300m)
V7 3Vin 0 PULSE(0 3.3 5m 5m 5m 250m 300m)
Rload1 5Vout 0 2
Rload2 3Vout 0 0.87
Rload3 N005 0 18
.tran 550m

* LTspice schematic (.asc)
Version 4
SHEET 1 1632 1552
WIRE -752 -776 -768 -776
WIRE 112 -776 -752 -776
WIRE 128 -776 112 -776
WIRE 224 -776 208 -776
WIRE 288 -776 224 -776
WIRE 560 -776 384 -776
WIRE 688 -776 560 -776
WIRE 816 -776 688 -776
WIRE -768 -760 -768 -776
WIRE 560 -760 560 -776
WIRE 688 -760 688 -776
WIRE 368 -680 368 -728
WIRE -768 -664 -768 -680
WIRE 560 -664 560 -696
WIRE 688 -664 688 -680
WIRE -752 -568 -768 -568
WIRE -336 -568 -752 -568
WIRE -320 -568 -336 -568
WIRE -224 -568 -240 -568
WIRE -192 -568 -224 -568
WIRE 0 -568 -96 -568
WIRE 560 -568 0 -568
WIRE 688 -568 560 -568
WIRE -768 -552 -768 -568
WIRE 560 -552 560 -568
WIRE 688 -552 688 -568
WIRE -112 -472 -112 -520
WIRE -768 -456 -768 -472
WIRE 560 -456 560 -488
WIRE 688 -456 688 -472
WIRE -688 -344 -800 -344
WIRE -640 -344 -688 -344
WIRE -480 -344 -544 -344
WIRE -336 -344 -336 -568
WIRE -336 -344 -400 -344
WIRE -112 -344 -112 -392
WIRE 368 -344 368 -600
WIRE 368 -344 -112 -344
WIRE 416 -344 368 -344
WIRE 560 -344 496 -344
WIRE -800 -328 -800 -344
WIRE 560 -328 560 -344
WIRE -592 -248 -592 -280
WIRE -512 -248 -592 -248
WIRE -336 -248 -336 -344
WIRE -336 -248 -432 -248
WIRE 560 -248 560 -264
WIRE -800 -232 -800 -248
WIRE 816 -216 816 -776
WIRE 816 -216 352 -216
WIRE -592 -184 -592 -248
WIRE 464 -184 -592 -184
WIRE -336 -152 -336 -248
WIRE -224 -152 -224 -568
WIRE -112 -152 -112 -344
WIRE 0 -152 0 -568
WIRE 112 -152 112 -776
WIRE 224 -152 224 -776
WIRE 352 -152 352 -216
WIRE -416 -72 -448 -72
WIRE 464 -40 464 -184
WIRE 464 -40 432 -40
WIRE 496 -40 464 -40
WIRE 592 -40 576 -40
WIRE 672 -40 656 -40
WIRE -688 -8 -688 -344
WIRE -416 -8 -688 -8
WIRE -736 56 -752 56
WIRE -416 56 -656 56
WIRE 560 72 432 72
WIRE -416 120 -544 120
WIRE -736 184 -752 184
WIRE -544 184 -544 120
WIRE -544 184 -656 184
WIRE -416 184 -528 184
WIRE 448 184 432 184
WIRE -416 248 -448 248
WIRE 560 264 560 72
WIRE -528 296 -528 184
WIRE -96 312 -96 296
WIRE -16 312 -96 312
WIRE 304 312 304 296
WIRE 384 312 304 312
WIRE -16 328 -16 312
WIRE 384 328 384 312
WIRE -96 344 -96 312
WIRE 304 344 304 312
WIRE -448 360 -448 248
WIRE -96 440 -96 408
WIRE -16 440 -16 408
WIRE -16 440 -96 440
WIRE 304 440 304 408
WIRE 384 440 384 408
WIRE 384 440 304 440
WIRE -96 456 -96 440
WIRE 304 456 304 440
WIRE -640 520 -656 520
WIRE -528 520 -528 376
WIRE -528 520 -560 520
WIRE -448 520 -448 440
WIRE -448 520 -528 520
WIRE 560 520 560 344
WIRE 560 520 -448 520
WIRE 128 552 128 296
WIRE -272 664 -272 296
WIRE 128 664 128 632
WIRE -272 776 -272 744
FLAG 560 -664 0
FLAG 688 -664 0
FLAG 560 -248 0
FLAG -752 184 0
FLAG 560 -456 0
FLAG 688 -456 0
FLAG -656 520 0
FLAG 512 184 0
FLAG -448 -72 0
FLAG 688 -776 5Vout
FLAG 688 -568 3Vout
FLAG -752 -568 3Vin
FLAG -752 -776 5Vin
FLAG -752 56 0
FLAG 672 -40 0
FLAG -800 -232 0
FLAG -272 776 0
FLAG 128 664 0
FLAG -96 456 0
FLAG 304 456 0
FLAG -768 -664 0
FLAG -768 -456 0
SYMBOL res 112 -760 R270
SYMATTR InstName R1
SYMATTR Value 7m
SYMBOL nmos 288 -728 R270
SYMATTR InstName Q1
SYMATTR Value IRF7413
SYMBOL res 352 -696 R0
SYMATTR InstName R2
SYMATTR Value 10
SYMBOL res 512 -360 R90
SYMATTR InstName R3
SYMATTR Value 1K
SYMBOL nmos -192 -520 R270
SYMATTR InstName Q2
SYMATTR Value IRF7413
SYMBOL res -128 -488 R0
SYMATTR InstName R4
SYMATTR Value 10
SYMBOL res -336 -552 R270
SYMATTR InstName R5
SYMATTR Value 5m
SYMBOL cap 544 -328 R0
SYMATTR InstName C1
SYMATTR Value 0.01
SYMBOL voltage -544 520 R90
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL res -544 280 R0
SYMATTR InstName R6
SYMATTR Value 10K
SYMBOL cap 544 -552 R0
SYMATTR InstName C2
SYMATTR Value 30
SYMBOL cap 448 200 R270
SYMATTR InstName C3
SYMATTR Value 0.1
SYMBOL cap 544 -760 R0
SYMATTR InstName C4
SYMATTR Value 30
SYMBOL res -464 344 R0
SYMATTR InstName R7
SYMATTR Value 10K
SYMBOL voltage -640 56 R90
SYMATTR InstName V2
SYMATTR Value PWL(0 0 10m 0 +1u 3.3)
SYMBOL res 544 360 M180
SYMATTR InstName R8
SYMATTR Value 10K
SYMBOL res 592 -56 R90
SYMATTR InstName R9
SYMATTR Value 18
SYMBOL cap 656 -56 R90
SYMATTR InstName C5
SYMATTR Value 4.7n
SYMBOL npn -544 -280 M270
SYMATTR InstName Q3
SYMATTR Value 2N2222
SYMBOL res -384 -360 R90
SYMATTR InstName R10
SYMATTR Value 12
SYMBOL res -416 -264 R90
SYMATTR InstName R11
SYMATTR Value 1K
SYMBOL LTC1644 0 72 R0
SYMATTR InstName U1
SYMBOL res -32 312 R0
SYMATTR InstName R12
SYMATTR Value 30
SYMBOL cap -112 344 R0
SYMATTR InstName C6
SYMATTR Value 10
SYMBOL res 368 312 R0
SYMATTR InstName R13
SYMATTR Value 150
SYMBOL cap 288 344 R0
SYMATTR InstName C7
SYMATTR Value 10
SYMBOL voltage -640 184 R90
SYMATTR InstName V3
SYMATTR Value PWL(0 3.3 40m 3.3 +1u 0)
SYMBOL voltage 128 536 R0
SYMATTR Value PULSE(0 -12 5m 5m 5m 400m 450m)
SYMATTR InstName V4
SYMBOL voltage -272 648 R0
SYMATTR InstName V5
SYMATTR Value PULSE(0 12 5m 5m 5m 400m 450m)
SYMBOL voltage -768 -776 R0
SYMATTR InstName V6
SYMATTR Value PULSE(0 5 5m 5m 5m 250m 300m)
SYMBOL voltage -768 -568 R0
SYMATTR InstName V7
SYMATTR Value PULSE(0 3.3 5m 5m 5m 250m 300m)
SYMBOL res 672 -776 R0
SYMATTR InstName Rload1
SYMATTR Value 2
SYMBOL res 672 -568 R0
SYMATTR InstName Rload2
SYMATTR Value 0.87
SYMBOL res -816 -344 R0
SYMATTR InstName Rload3
SYMATTR Value 18