Version 4
SHEET 1 880 800
WIRE 128 176 -144 176
WIRE 368 176 128 176
WIRE -144 192 -144 176
WIRE 128 192 128 176
WIRE 368 208 368 176
WIRE 304 256 272 256
WIRE 480 272 432 272
WIRE -144 288 -144 272
WIRE 128 288 128 272
WIRE 304 288 128 288
WIRE 128 304 128 288
WIRE 272 320 272 256
WIRE 304 320 272 320
WIRE 272 352 272 320
WIRE 304 352 272 352
WIRE 128 400 128 384
WIRE 336 432 336 400
WIRE 400 432 400 400
FLAG -144 288 0
FLAG 400 432 0
FLAG 336 432 0
FLAG 128 400 0
FLAG 480 272 OUT
FLAG -144 176 Vcc
SYMBOL voltage -144 176 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PWL(0 0 1m 3.3)
SYMBOL Comparators\\LTC1440 368 208 R0
SYMATTR InstName U1
SYMBOL res 112 288 R0
SYMATTR InstName R1
SYMATTR Value 1.13Meg
SYMBOL res 112 176 R0
SYMATTR InstName R2
SYMATTR Value 1.65Meg
TEXT 464 456 Left 2 !.tran 1m
TEXT 256 160 Bottom 2 ;µPower 2.9V Vcc Threshold Detector