Version 4
SHEET 1 1216 680
WIRE 176 -48 144 -48
WIRE 304 -48 240 -48
WIRE 0 32 -144 32
WIRE 144 32 144 -48
WIRE 144 32 0 32
WIRE 176 32 144 32
WIRE 304 32 304 -48
WIRE 304 32 256 32
WIRE 208 80 -288 80
WIRE 0 112 0 32
WIRE 208 112 208 80
WIRE 144 128 144 32
WIRE 176 128 144 128
WIRE 304 144 304 32
WIRE 304 144 240 144
WIRE 176 160 160 160
WIRE -384 224 -480 224
WIRE -384 368 -384 224
WIRE -288 368 -288 80
WIRE -144 368 -144 32
WIRE -384 480 -384 448
WIRE -288 480 -288 448
WIRE -288 480 -384 480
WIRE -144 480 -144 448
WIRE -144 480 -288 480
WIRE 0 480 0 176
WIRE 0 480 -144 480
WIRE 160 480 160 160
WIRE 160 480 0 480
WIRE 160 528 160 480
WIRE -480 624 -480 224
WIRE 208 624 208 176
WIRE 208 624 -480 624
FLAG 160 528 0
SYMBOL voltage -288 352 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 17.5V
SYMBOL voltage -384 464 R180
WINDOW 0 24 96 Left 2
WINDOW 3 24 16 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 24 -12 Left 2
SYMATTR InstName V3
SYMATTR Value 17.5V
SYMBOL Opamps\\LT1028 208 80 R0
SYMATTR InstName U2
SYMBOL res 272 16 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R6
SYMATTR Value 90
SYMBOL cap 240 -64 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C3
SYMATTR Value 2nF
SYMBOL cap -16 112 R0
SYMATTR InstName C4
SYMATTR Value 5nF
SYMBOL current -144 368 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName I1
SYMATTR Value SINE(0 0.02 1000)
TEXT -368 576 Left 2 !.tran 50m startup