* SPICE netlist
MQ1 IN N005 N007 N007 Si7850DP
D1 N001 N004 MBRS1100
C1 N004 N007 .22
R1 IN N002 1Meg
C2 N009 0 680p Rser=10K Cpar=120p
D2 0 N007 PDS760
L1 N007 N008 10
R3 N008 OUT 15m
R4 N006 0 49.9K
C3 N003 0 1000p
C4 OUT 0 100 Rser=50m
V1 IN 0 48
D3 OUT N001 1N4148
R5 N010 OUT 130K
R6 0 N010 14.7K
C5 N001 0 1
R7 N002 0 82.5K
Rload OUT 0 2.9
XU1 IN N002 N003 0 N010 N009 MP_01 N006 0 OUT N008 0 N001 N007 N005 N004 LT3844 ;pnba Vin)_SHDN)Css)Burst_EN)FB)Vc))Fset)SGND)Sense-)Sense+)PGND)Vcc)SW)TG)Boost
.tran 1m startup

* LTspice schematic (.asc)
Version 4
SHEET 1 1280 704
WIRE -528 -352 -640 -352
WIRE -128 -352 -528 -352
WIRE 256 -352 -128 -352
WIRE -640 -336 -640 -352
WIRE -528 -336 -528 -352
WIRE -128 -288 -128 -352
WIRE 336 -288 112 -288
WIRE 496 -288 400 -288
WIRE -640 -240 -640 -256
WIRE -528 -240 -528 -256
WIRE -320 -240 -528 -240
WIRE 112 -240 112 -288
WIRE 112 -240 64 -240
WIRE 144 -240 112 -240
WIRE -528 -224 -528 -240
WIRE 112 -224 112 -240
WIRE -400 -144 -416 -144
WIRE -320 -144 -336 -144
WIRE 112 -144 112 -160
WIRE 112 -144 64 -144
WIRE -528 -128 -528 -144
WIRE 112 -128 112 -144
WIRE 256 -128 256 -352
WIRE -320 -48 -352 -48
WIRE 208 -48 64 -48
WIRE -432 48 -448 48
WIRE -320 48 -352 48
WIRE 112 48 112 -64
WIRE 112 48 64 48
WIRE 208 48 112 48
WIRE 256 48 256 -32
WIRE 256 48 208 48
WIRE 288 48 256 48
WIRE 384 48 368 48
WIRE 400 48 384 48
WIRE 496 48 496 -288
WIRE 496 48 480 48
WIRE 544 48 496 48
WIRE 640 48 544 48
WIRE 544 64 544 48
WIRE 640 64 640 48
WIRE 208 80 208 48
WIRE -432 144 -448 144
WIRE -320 144 -368 144
WIRE 112 144 64 144
WIRE 208 160 208 144
WIRE 544 160 544 128
WIRE 640 160 640 144
WIRE 112 192 112 144
WIRE 384 192 384 48
WIRE 384 192 112 192
WIRE -320 240 -352 240
WIRE 496 240 496 48
WIRE 496 240 64 240
WIRE -192 304 -192 288
WIRE -64 304 -64 288
WIRE -464 336 -480 336
WIRE -352 336 -352 240
WIRE -352 336 -384 336
WIRE 320 336 -352 336
WIRE 496 336 496 240
WIRE 496 336 400 336
FLAG -448 144 0
FLAG -64 304 0
FLAG 544 160 0
FLAG 640 160 0
FLAG -640 -240 0
FLAG 640 48 OUT
FLAG -640 -352 IN
FLAG 208 160 0
FLAG -192 304 0
FLAG -416 -144 0
FLAG -352 -48 0
FLAG -448 48 0
FLAG -480 336 0
FLAG 208 -240 0
FLAG -528 -128 0
SYMBOL nmos 208 -128 R0
SYMATTR InstName Q1
SYMATTR Value Si7850DP
SYMBOL schottky 96 -224 R0
SYMATTR InstName D1
SYMATTR Value MBRS1100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL cap 96 -128 R0
SYMATTR Value .22
SYMATTR InstName C1
SYMBOL res -544 -352 R0
SYMATTR InstName R1
SYMATTR Value 1Meg
SYMBOL cap -368 128 R90
SYMATTR InstName C2
SYMATTR Value 680p
SYMATTR SpiceLine Rser=10K Cpar=120p
SYMBOL schottky 192 144 M180
SYMATTR InstName D2
SYMATTR Value PDS760
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL ind 272 64 R270
SYMATTR InstName L1
SYMATTR Value 10
SYMBOL res 384 64 R270
SYMATTR InstName R3
SYMATTR Value 15m
SYMBOL res -336 32 R90
SYMATTR InstName R4
SYMATTR Value 49.9K
SYMBOL cap -336 -160 R90
SYMATTR InstName C3
SYMATTR Value 1000p
SYMBOL cap 528 64 R0
SYMATTR InstName C4
SYMATTR Value 100
SYMATTR SpiceLine Rser=50m
SYMBOL voltage -640 -352 R0
SYMATTR Value 48
SYMATTR InstName V1
SYMBOL diode 400 -304 R90
SYMATTR InstName D3
SYMATTR Value 1N4148
SYMBOL res 304 352 R270
SYMATTR InstName R5
SYMATTR Value 130K
SYMBOL res -480 352 R270
SYMATTR InstName R6
SYMATTR Value 14.7K
SYMBOL cap 144 -256 M90
SYMATTR InstName C5
SYMATTR Value 1
SYMBOL res -544 -240 R0
SYMATTR InstName R7
SYMATTR Value 82.5K
SYMBOL res 624 48 R0
SYMATTR InstName Rload
SYMATTR Value 2.9
SYMBOL PowerProducts\\LT3844 -128 0 R0
SYMATTR InstName U1