Version 4
SHEET 1 1328 1060
WIRE -512 64 -512 48
WIRE -512 160 -512 144
WIRE -480 -208 -512 -208
WIRE -480 48 -512 48
WIRE -464 -64 -512 -64
WIRE -384 -208 -400 -208
WIRE -384 -112 -384 -208
WIRE -384 -64 -400 -64
WIRE -384 -64 -384 -112
WIRE -384 16 -384 -64
WIRE -352 -112 -384 -112
WIRE -336 16 -384 16
WIRE -336 48 -480 48
WIRE -304 -208 -384 -208
WIRE -256 -112 -272 -112
WIRE -176 -208 -224 -208
WIRE -176 -112 -192 -112
WIRE -176 -112 -176 -208
WIRE -176 32 -272 32
WIRE -144 32 -176 32
WIRE -32 32 -64 32
WIRE -32 48 -32 32
WIRE -32 144 -32 112
WIRE 48 32 -32 32
WIRE 80 -208 -176 -208
WIRE 80 32 48 32
WIRE 80 32 80 -208
WIRE 80 48 80 32
WIRE 80 144 80 128
WIRE 128 32 80 32
WIRE 256 32 208 32
WIRE 256 48 256 32
WIRE 256 144 256 112
WIRE 304 32 256 32
WIRE 416 32 384 32
WIRE 432 32 416 32
WIRE 432 48 432 32
WIRE 432 144 432 112
FLAG -32 144 0
FLAG 80 144 0
FLAG -512 160 0
FLAG -512 -208 0
FLAG -176 32 x
FLAG -480 48 i
FLAG 48 32 o
FLAG -512 -64 0
FLAG 256 144 0
FLAG 432 144 0
FLAG 416 32 lp
SYMBOL ind -160 48 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
WINDOW 39 63 58 VTop 0
SYMATTR InstName Lo
SYMATTR Value 30µ
SYMATTR SpiceLine Rser=10m Rpar=10k
SYMBOL cap -48 48 R0
SYMATTR InstName Co
SYMATTR Value 680n
SYMBOL res 64 32 R0
SYMATTR InstName Ro
SYMATTR Value {Ro}
SYMBOL res -384 -224 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R1
SYMATTR Value {R1}
SYMBOL res -208 -224 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value {R2}
SYMBOL res -256 -128 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R3
SYMATTR Value 1k0
SYMBOL cap -192 -128 R90
WINDOW 0 0 32 VBottom 0
WINDOW 3 32 32 VTop 0
SYMATTR InstName C2
SYMATTR Value 150p
SYMBOL cap -400 -80 R90
WINDOW 0 0 32 VBottom 0
WINDOW 3 32 32 VTop 0
SYMATTR InstName C1
SYMATTR Value 33p
SYMBOL Digital\\diffschmtbuf -336 96 M180
WINDOW 3 0 16 Left 0
WINDOW 123 0 -8 Left 0
WINDOW 0 0 112 Left 0
WINDOW 39 0 -32 Left 0
SYMATTR Value Vhigh=50 Vlow=-50
SYMATTR Value2 Rout=30m Tau=30n
SYMATTR InstName A1
SYMATTR SpiceLine Td=135ns tripdt=0.1n
SYMATTR SpiceLine2 Vt=0 Vh=0
SYMBOL voltage -512 48 R0
WINDOW 0 53 70 Bottom 0
WINDOW 3 28 122 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 60 56 VTop 0
SYMATTR InstName Vi
SYMATTR Value SINE({dc/gain} {sqrt(2)*ac/gain} {fi})
SYMBOL ind 112 48 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
WINDOW 39 63 58 VTop 0
SYMATTR InstName Lo1
SYMATTR Value {Lr}
SYMATTR SpiceLine Rser={Rr}
SYMBOL cap 272 48 M0
SYMATTR InstName Co1
SYMATTR Value {Cr}
SYMBOL ind 288 48 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
WINDOW 39 63 58 VTop 0
SYMATTR InstName Lo2
SYMATTR Value {Lr*100}
SYMATTR SpiceLine Rser={Rr*100}
SYMBOL cap 416 48 R0
SYMATTR InstName Co2
SYMATTR Value {Cr/100}
TEXT -488 272 Left 0 ;.step param Ro list 1G 8 4; 6 1u
TEXT -488 208 Left 0 !.param dc=0 ac=1 Ro=6 fi=5k
TEXT 128 -272 Left 0 !.four {fi} {int(fr/fi)} {nc} V(lp) ; freq, harmonics, periods, source\n.save V(lp) ; save low pass output
TEXT 128 -144 Left 0 !.param Tdata=nc/2/fi ; depends on settling time of simulation\n.param dt=1/fi/nfft ; calculated based on above inputs\n.param Tend=Tdata+dt+nc/fi ; calculated to yield nc cycles of data
TEXT 32 288 Left 0 !.tran {dt} {Tend} {Tdata} {dt} uic ; uic required for switching amps
TEXT -488 240 Left 0 !.step param dc list 30 40 45 48 ; 50
TEXT 128 -208 Left 0 !.options numdgt=16 ; no data digit compression\n.options plotwinsize=0 ; no data time compression
TEXT -488 304 Left 0 !.param nfft=16384 nc=16
TEXT -496 -272 Left 0 !.param R1=1k8 R2=8k2 gain=R2/R1+1
TEXT 128 192 Left 0 !.param Rr=1k2 fr=50k\n.param Lr=500/pi/fr Cr=500u/pi/fr ; Zr=1k
TEXT -240 -376 Left 0 ;Run an FFT on the output and note how distortion increases the nearer\nthe output gets to the output rail (supply) voltage