Version 4
SHEET 1 880 680
WIRE -96 -64 -256 -64
WIRE -96 -16 -96 -64
WIRE 96 16 48 16
WIRE 192 16 160 16
WIRE -96 112 -96 64
WIRE -64 112 -96 112
WIRE 48 112 48 16
WIRE 48 112 -64 112
WIRE 96 112 48 112
WIRE 192 112 192 16
WIRE 192 112 176 112
WIRE -96 128 -96 112
WIRE -96 128 -192 128
WIRE -96 176 -96 128
WIRE 0 176 -96 176
WIRE 192 192 192 112
WIRE 192 192 64 192
WIRE 384 192 192 192
WIRE 0 208 -96 208
WIRE -192 240 -192 128
WIRE -96 256 -96 208
WIRE -256 352 -256 -64
WIRE -192 352 -192 304
WIRE -96 352 -96 336
FLAG -96 352 0
FLAG -256 352 0
FLAG 384 192 out
FLAG -96 208 ref
FLAG -64 112 in-
FLAG -192 352 0
SYMBOL voltage -96 240 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value 2.5
SYMBOL current -96 -16 R0
WINDOW 3 16 -39 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value PULSE(0 100n 1u 1p 1p 10n 1)
SYMATTR InstName I1
SYMBOL res 192 96 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value {Rf}
SYMBOL Opamps\\opamp 32 128 R0
SYMATTR InstName U1
SYMATTR SpiceLine2 GBW=130k
SYMBOL cap -208 240 R0
SYMATTR InstName C1
SYMATTR Value 50p
SYMBOL cap 160 0 R90
WINDOW 0 58 32 VBottom 2
WINDOW 3 -30 37 VTop 2
SYMATTR InstName C2
SYMATTR Value {2p*10000/sqrt(Rf)}
TEXT -8 328 Left 2 !.tran 0 5m 0 1n
TEXT 40 240 Left 2 !.lib opamp.sub
TEXT -8 288 Left 2 !.step param Rf 100MEG 200MEG 100MEG