Version 4
SHEET 1 880 680
WIRE -320 208 -320 176
WIRE -320 320 -320 288
WIRE -64 512 -64 208
WIRE -16 384 -16 240
WIRE 0 176 -320 176
WIRE 16 208 -64 208
WIRE 16 240 -16 240
WIRE 32 288 32 272
WIRE 32 384 -16 384
WIRE 32 384 32 368
WIRE 32 416 32 384
WIRE 32 512 -64 512
WIRE 32 512 32 496
WIRE 32 528 32 512
WIRE 32 624 32 608
WIRE 64 272 32 272
WIRE 112 176 0 176
WIRE 112 208 16 208
WIRE 112 240 16 240
WIRE 112 272 64 272
WIRE 144 352 144 320
WIRE 176 128 176 80
WIRE 176 544 176 512
WIRE 176 624 176 608
WIRE 208 80 176 80
WIRE 208 512 176 512
WIRE 288 192 256 192
FLAG -320 320 0
FLAG 208 512 VCC
FLAG 208 80 VCC
FLAG 176 624 0
FLAG 288 192 OUT
FLAG 32 624 0
FLAG 144 352 0
FLAG 0 176 IN
FLAG 64 272 REF
FLAG 16 208 REF1
FLAG 16 240 HYST
SYMBOL Misc\\cell 176 544 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL voltage -320 192 R0
WINDOW 3 -63 169 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value PULSE(0 2 0 1m 1m 1u 2m)
SYMATTR InstName V2
SYMBOL MAX921 176 128 R0
SYMATTR InstName U1
SYMBOL res 16 272 R0
SYMATTR InstName R1
SYMATTR Value 47k
SYMBOL res 16 512 R0
SYMATTR InstName R2
SYMATTR Value 1MEG
SYMBOL res 16 400 R0
SYMATTR InstName R3
SYMATTR Value 120k
TEXT -338 76 Left 0 !.tran 0 5m 0
TEXT -336 -408 Left 0 ;The MAX921 model required a change to get the hysteresis control feature!\nTotal hysteresis is 2*(V(REF-V(HYST)).\n \n* Next line added to repair the model for hysteresis \nBI51 51 0 I=(V(3)+V(4))*0.5e-6\n \nThere is still  another issue with some amount of dependence of \nthe hysteresis from the voltage on the Vin- input pin.\n \nTry with the Alternate solver to see which solver is faster with your circuit.\nControl Panel -> SPICE Solver: Alternate\nPlot V(IN) and V(OUT).\n \nThe symbol points to the model file MAX921.FAM .\nKeep the symbol, model and schematic in one folder.
TEXT -344 104 Left 0 !.options plotwinsize=0
TEXT -40 488 Left 0 ;1V