* SPICE netlist
V1 COM 0 6V
V2 FREF 0 PULSE(0 6 0 0.00000001 0.00000001 0.0000045 0.000005)
Cant ANT 0 8pF
Chand ANT 0 {Chand}
R1 COM ANT 330000
D3 ANT COM D
D4 0 ANT D
C6 COM ANT 1.5pF
C7 ANT 0 1.5pF
XU2 0 FREF OUT COM N001 ANT ANT COM NE555 ;pnba GND)TRIG)OUT)RST)CV)THRS)DIS)Vcc
C1 N001 0 1nF
Cant1 ANT2 0 8pF
Chand1 ANT2 0 {Chand}
R2 ANT2 N005 100000
XU1 0 FREF OUT2 COM N006 ANT2 ANT2 COM NE555 ;pnba GND)TRIG)OUT)RST)CV)THRS)DIS)Vcc
C2 N006 0 1nF
D1 COM N002 D
D2 N002 N003 D
D5 N003 N004 D
D6 N004 N005 D
.tran 0 0.000333 0.0003 0.000000001 startup
.step param Chand list 0pF 0.1pF 0.2pF 0.3pF 0.4pF 0.5pF 0.6pF 0.7pF 0.8pF 0.9pF 1pF 1.1pF 1.2pF 1.3pF 1.4pF 1.5pF
.MEAS TRAN res1 FIND V(out) AT=1m

* LTspice schematic (.asc)
Version 4
SHEET 1 1776 1888
WIRE 808 -880 808 -944
WIRE 808 -880 760 -880
WIRE -712 -832 -744 -832
WIRE 760 -832 760 -880
WIRE 808 -832 808 -880
WIRE -888 -800 -888 -848
WIRE 760 -736 760 -768
WIRE 808 -736 808 -768
WIRE 808 -736 760 -736
WIRE 888 -736 808 -736
WIRE 760 -704 760 -736
WIRE 808 -704 808 -736
WIRE -888 -688 -888 -720
WIRE -744 -672 -744 -832
WIRE 760 -608 760 -640
WIRE 808 -608 808 -640
WIRE 808 -608 760 -608
WIRE -744 -560 -744 -592
WIRE 808 -560 808 -608
WIRE -88 -368 -152 -368
WIRE 200 -368 136 -368
WIRE -88 -304 -504 -304
WIRE 248 -304 136 -304
WIRE 360 -304 248 -304
WIRE 504 -304 440 -304
WIRE -88 -240 -504 -240
WIRE 248 -240 248 -304
WIRE 248 -240 136 -240
WIRE 664 -240 664 -320
WIRE 664 -240 248 -240
WIRE 744 -240 664 -240
WIRE -88 -176 -152 -176
WIRE 184 -176 136 -176
WIRE 664 -160 664 -240
WIRE 744 -160 744 -240
WIRE 184 -144 184 -176
WIRE 184 -48 184 -80
WIRE 664 -32 664 -96
WIRE 744 -32 744 -96
WIRE 360 48 360 16
WIRE 360 144 360 112
WIRE 360 256 360 208
WIRE 360 368 360 320
WIRE 360 544 360 432
WIRE -88 608 -152 608
WIRE 200 608 136 608
WIRE -88 672 -504 672
WIRE 360 672 360 624
WIRE 360 672 136 672
WIRE -88 736 -504 736
WIRE 360 736 360 672
WIRE 360 736 136 736
WIRE 664 736 664 656
WIRE 664 736 360 736
WIRE 744 736 664 736
WIRE -88 800 -152 800
WIRE 184 800 136 800
WIRE 664 816 664 736
WIRE 744 816 744 736
WIRE 184 832 184 800
WIRE 184 928 184 896
WIRE 664 944 664 880
WIRE 744 944 744 880
FLAG -888 -688 0
FLAG -712 -832 FREF
IOPIN 224 -48 Out
FLAG -744 -560 0
FLAG 664 -320 ANT
FLAG 664 -32 0
FLAG 744 -32 0
FLAG -504 -304 FREF
IOPIN 432 480 In
FLAG -888 -848 COM
FLAG 808 -560 0
FLAG 808 -944 COM
FLAG 888 -736 ANT
FLAG 200 -368 COM
FLAG -152 -368 0
FLAG -152 -176 COM
FLAG 184 -48 0
FLAG 504 -304 COM
FLAG -504 -240 OUT
FLAG 664 656 ANT2
FLAG 664 944 0
FLAG 744 944 0
FLAG -504 672 FREF
IOPIN 432 1456 In
FLAG 200 608 COM
FLAG -152 608 0
FLAG -152 800 COM
FLAG 184 928 0
FLAG 360 16 COM
FLAG -504 736 OUT2
SYMBOL voltage -888 -816 R0
SYMATTR InstName V1
SYMATTR Value 6V
SYMBOL voltage -744 -688 R0
SYMATTR InstName V2
SYMATTR Value PULSE(0 6 0 0.00000001 0.00000001 0.0000045 0.000005)
SYMBOL cap 648 -160 R0
SYMATTR InstName Cant
SYMATTR Value 8pF
SYMBOL cap 728 -160 R0
SYMATTR InstName Chand
SYMATTR Value {Chand}
SYMBOL res 456 -320 R90
SYMATTR InstName R1
SYMATTR Value 330000
SYMBOL diode 776 -768 R180
SYMATTR InstName D3
SYMBOL diode 776 -640 R180
SYMATTR InstName D4
SYMBOL cap 792 -832 R0
SYMATTR InstName C6
SYMATTR Value 1.5pF
SYMBOL cap 792 -704 R0
SYMATTR InstName C7
SYMATTR Value 1.5pF
SYMBOL NE555 24 -272 R0
SYMATTR InstName U2
SYMBOL cap 168 -144 R0
SYMATTR InstName C1
SYMATTR Value 1nF
SYMBOL cap 648 816 R0
SYMATTR InstName Cant1
SYMATTR Value 8pF
SYMBOL cap 728 816 R0
SYMATTR InstName Chand1
SYMATTR Value {Chand}
SYMBOL res 376 640 R180
SYMATTR InstName R2
SYMATTR Value 100000
SYMBOL NE555 24 704 R0
SYMATTR InstName U1
SYMBOL cap 168 832 R0
SYMATTR InstName C2
SYMATTR Value 1nF
SYMBOL diode 344 48 R0
SYMATTR InstName D1
SYMBOL diode 344 144 R0
SYMATTR InstName D2
SYMBOL diode 344 256 R0
SYMATTR InstName D5
SYMBOL diode 344 368 R0
SYMATTR InstName D6