* SPICE netlist
XU1 N006 N009 N005 N012 N010 0 N008 MP_01 IN N001 N002 0 N007 IN MP_02 N006 LT1680 ;pnba SL/ADJ)Ct)Iave)SS)Vc)SGND)FB))Sense+)Sense-)Run/SHDN)PGND)GATE)12Vin))5Vref
MQ1 N003 N007 0 0 Si4410DY
R1 IN N001 5m
L1 N001 N003 25
C1 N005 N004 2.2n
R2 IN N002 100K
C2 N012 0 .01
C3 N009 0 1000p
R3 N006 N009 15K
V1 IN 0 12
D1 N003 OUT MBRS1100
C4 OUT 0 680 Rser=.1
R4 OUT N008 75K
R5 N008 0 2K
R6 N011 0 4.7K
C5 N010 N011 .0047
Rload OUT 0 20
C6 N006 0 1
R8 N004 0 2K
.tran 8m startup

* LTspice schematic (.asc)
Version 4
SHEET 1 1168 544
WIRE -472 -272 -584 -272
WIRE -168 -272 -472 -272
WIRE 56 -272 -168 -272
WIRE 88 -272 56 -272
WIRE 184 -272 168 -272
WIRE -584 -256 -584 -272
WIRE -472 -256 -472 -272
WIRE -168 -208 -168 -272
WIRE 184 -208 184 -272
WIRE 184 -208 104 -208
WIRE 184 -192 184 -208
WIRE -584 -160 -584 -176
WIRE -472 -144 -472 -176
WIRE -360 -144 -472 -144
WIRE 56 -144 56 -272
WIRE 56 -144 24 -144
WIRE 184 -96 184 -112
WIRE 280 -96 184 -96
WIRE 392 -96 344 -96
WIRE 488 -96 392 -96
WIRE 584 -96 488 -96
WIRE -552 -80 -584 -80
WIRE -456 -80 -472 -80
WIRE -360 -80 -392 -80
WIRE 104 -80 104 -208
WIRE 104 -80 24 -80
WIRE 488 -80 488 -96
WIRE 584 -80 584 -96
WIRE 392 -64 392 -96
WIRE -472 -16 -568 -16
WIRE -376 -16 -472 -16
WIRE -360 -16 -376 -16
WIRE 136 -16 24 -16
WIRE -568 0 -568 -16
WIRE -472 0 -472 -16
WIRE 184 16 184 0
WIRE 488 16 488 -16
WIRE 584 16 584 0
WIRE -376 48 -376 -16
WIRE -360 48 -376 48
WIRE 392 48 392 16
WIRE 392 48 24 48
WIRE 392 64 392 48
WIRE -568 80 -568 64
WIRE -472 112 -472 80
WIRE -360 112 -472 112
WIRE 40 112 24 112
WIRE 120 112 104 112
WIRE 216 112 200 112
WIRE -472 128 -472 112
WIRE 392 160 392 144
WIRE -296 192 -296 176
WIRE -168 192 -168 176
WIRE -40 192 -40 176
WIRE -472 208 -472 192
WIRE -296 272 -296 256
FLAG 184 16 0
FLAG -584 -80 0
FLAG -472 208 0
FLAG -296 272 0
FLAG -168 192 0
FLAG -40 192 0
FLAG -584 -160 0
FLAG 488 16 0
FLAG 392 160 0
FLAG 216 112 0
FLAG 584 16 0
FLAG -568 80 0
FLAG 584 -96 OUT
FLAG -584 -272 IN
SYMBOL POWERPRODUCTS\\LT1680 -168 -16 R0
SYMATTR InstName U1
SYMBOL NMOS 136 -96 R0
SYMATTR InstName Q1
SYMATTR Value Si4410DY
SYMBOL RES 72 -256 R270
SYMATTR InstName R1
SYMATTR Value 5m
SYMBOL ind 168 -208 R0
SYMATTR InstName L1
SYMATTR Value 25
SYMBOL cap -392 -96 R90
SYMATTR InstName C1
SYMATTR Value 2.2n
SYMBOL res -488 -272 R0
SYMATTR InstName R2
SYMATTR Value 100K
SYMBOL cap -312 192 R0
SYMATTR InstName C2
SYMATTR Value .01
SYMBOL cap -488 128 R0
SYMATTR InstName C3
SYMATTR Value 1000p
SYMBOL res -488 -16 R0
SYMATTR InstName R3
SYMATTR Value 15K
SYMBOL VOLTAGE -584 -272 R0
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL schottky 280 -80 R270
SYMATTR InstName D1
SYMATTR Value MBRS1100
SYMBOL polcap 472 -80 R0
SYMATTR SpiceLine Rser=.1
SYMATTR InstName C4
SYMATTR Value 680
SYMBOL res 376 -80 R0
SYMATTR InstName R4
SYMATTR Value 75K
SYMBOL res 376 48 R0
SYMATTR InstName R5
SYMATTR Value 2K
SYMBOL res 104 128 R270
SYMATTR InstName R6
SYMATTR Value 4.7K
SYMBOL cap 40 128 R270
SYMATTR InstName C5
SYMATTR Value .0047
SYMBOL res 568 -96 R0
SYMATTR InstName Rload
SYMATTR Value 20
SYMBOL polcap -584 0 R0
SYMATTR InstName C6
SYMATTR Value 1
SYMBOL res -456 -96 R90
SYMATTR InstName R8
SYMATTR Value 2K