* SPICE netlist
Vphi1 phi1 0 PULSE(1 0 5n 0 0 5n 10n)
Vphi2 phi2 0 PULSE(1 0 5.2n 0 0 5n 10n)
Vphi3 phi3 0 PULSE(0 1 5.4n 0 0 4n 10n)
V1 Vinm 0 SINE(500m -100m 5MEG)
V2 Vinp 0 SINE(500m 100m 5MEG)
E1 vop N002 vp vm 1e6
E2 N002 vom vp vm 1e6
VCM N002 0 500mV
C1 vm N001 1p
C2 vp N003 1p
C3 voutp 0 1p
C4 voutm 0 1p
M1 N001 phi2 vinp 0 N_50n l=50n w=500n
M2 N003 phi2 vinm 0 N_50n l=50n w=500n
M3 vop phi1 vm 0 N_50n l=50n w=500n
M4 vom phi1 vp 0 N_50n l=50n w=500n
M5 vop phi3 N001 0 N_50n l=50n w=500n
M6 N003 phi3 vom 0 N_50n l=50n w=500n
M7 voutp phi3 vop 0 N_50n l=50n w=500n
M8 vom phi3 voutm 0 N_50n l=50n w=500n
.tran 0 200n 0 50p
.options reltol=0.01 abstol=1n vntol=100u

* LTspice schematic (.asc)
Version 4
SHEET 1 1120 1104
WIRE -496 424 -496 376
WIRE -448 -88 -560 -88
WIRE -416 -232 -560 -232
WIRE -416 376 -496 376
WIRE -384 376 -416 376
WIRE -336 392 -336 344
WIRE -288 -232 -320 -232
WIRE -288 -232 -288 -504
WIRE -288 -88 -352 -88
WIRE -288 152 -288 -88
WIRE -272 -232 -288 -232
WIRE -272 -88 -288 -88
WIRE -256 344 -336 344
WIRE -224 344 -256 344
WIRE -192 360 -192 312
WIRE -144 -504 -288 -504
WIRE -144 152 -288 152
WIRE -112 -232 -208 -232
WIRE -112 -88 -208 -88
WIRE -112 312 -192 312
WIRE -80 -232 -112 -232
WIRE -80 -232 -80 -392
WIRE -80 -88 -112 -88
WIRE -80 40 -80 -88
WIRE -80 312 -112 312
WIRE -48 -392 -80 -392
WIRE -48 -136 -48 -280
WIRE -48 -88 -80 -88
WIRE -48 -88 -48 -136
WIRE -48 40 -80 40
WIRE -32 -232 -80 -232
WIRE -32 -88 -32 -232
WIRE -16 296 -16 248
WIRE 0 -280 -48 -280
WIRE 0 -232 -32 -232
WIRE 0 -136 -48 -136
WIRE 0 -88 -32 -88
WIRE 16 248 -16 248
WIRE 48 -360 48 -392
WIRE 48 -296 48 -360
WIRE 48 -184 48 -216
WIRE 48 -152 48 -184
WIRE 48 8 48 -72
WIRE 48 40 48 8
WIRE 80 -504 -48 -504
WIRE 80 -360 48 -360
WIRE 80 -360 80 -504
WIRE 80 8 48 8
WIRE 80 152 -48 152
WIRE 80 152 80 8
WIRE 160 -360 80 -360
WIRE 160 -184 48 -184
WIRE 160 8 80 8
WIRE 192 472 192 424
WIRE 224 424 192 424
WIRE 320 -360 160 -360
WIRE 320 8 160 8
WIRE 448 8 416 8
WIRE 464 -360 416 -360
WIRE 560 -360 464 -360
WIRE 560 8 448 8
FLAG -496 504 0
FLAG -416 376 phi1
FLAG -336 472 0
FLAG -256 344 phi2
FLAG -192 440 0
FLAG -112 312 phi3
FLAG 192 552 0
FLAG 224 424 Vinm
FLAG -16 376 0
FLAG 16 248 Vinp
FLAG 160 -104 0
FLAG -112 -232 vm
FLAG -112 -88 vp
FLAG 160 -360 vop
FLAG 160 8 vom
FLAG 448 72 0
FLAG -368 -232 0
FLAG -400 -280 phi2
FLAG -400 -88 0
FLAG -432 -136 phi2
FLAG -560 -232 vinp
FLAG -560 -88 vinm
FLAG 0 -392 0
FLAG -32 -440 phi1
FLAG 0 40 0
FLAG -32 88 phi1
FLAG -96 -504 0
FLAG -128 -552 phi3
FLAG -96 152 0
FLAG -64 200 phi3
FLAG 368 -360 0
FLAG 336 -408 phi3
FLAG 368 8 0
FLAG 400 56 phi3
FLAG 464 -424 0
FLAG 560 -360 voutp
FLAG 560 8 voutm
SYMBOL voltage -496 408 R0
SYMATTR InstName Vphi1
SYMATTR Value PULSE(1 0 5n 0 0 5n 10n)
SYMBOL voltage -336 376 R0
SYMATTR InstName Vphi2
SYMATTR Value PULSE(1 0 5.2n 0 0 5n 10n)
SYMBOL voltage -192 344 R0
SYMATTR InstName Vphi3
SYMATTR Value PULSE(0 1 5.4n 0 0 4n 10n)
SYMBOL voltage 192 456 R0
SYMATTR InstName V1
SYMATTR Value SINE(500m -100m 5MEG)
SYMBOL voltage -16 280 R0
SYMATTR InstName V2
SYMATTR Value SINE(500m 100m 5MEG)
SYMBOL e 48 -312 R0
SYMATTR InstName E1
SYMATTR Value 1e6
SYMBOL e 48 -168 R0
SYMATTR InstName E2
SYMATTR Value 1e6
SYMBOL voltage 160 -200 R0
SYMATTR InstName VCM
SYMATTR Value 500mV
SYMBOL cap -208 -216 M270
SYMATTR InstName C1
SYMATTR Value 1p
SYMBOL cap -208 -72 M270
SYMATTR InstName C2
SYMATTR Value 1p
SYMBOL cap 480 -360 R180
SYMATTR InstName C3
SYMATTR Value 1p
SYMBOL cap 432 8 R0
SYMATTR InstName C4
SYMATTR Value 1p
SYMBOL nmos4 -320 -280 R90
SYMATTR InstName M1
SYMATTR Value N_50n
SYMATTR Value2 l=50n w=500n
SYMBOL nmos4 -352 -136 R90
SYMATTR InstName M2
SYMATTR Value N_50n
SYMATTR Value2 l=50n w=500n
SYMBOL nmos4 48 -440 R90
SYMATTR InstName M3
SYMATTR Value N_50n
SYMATTR Value2 l=50n w=500n
SYMBOL nmos4 48 88 M270
SYMATTR InstName M4
SYMATTR Value N_50n
SYMATTR Value2 l=50n w=500n
SYMBOL nmos4 -48 -552 R90
SYMATTR InstName M5
SYMATTR Value N_50n
SYMATTR Value2 l=50n w=500n
SYMBOL nmos4 -144 200 R270
SYMATTR InstName M6
SYMATTR Value N_50n
SYMATTR Value2 l=50n w=500n
SYMBOL nmos4 416 -408 R90
SYMATTR InstName M7
SYMATTR Value N_50n
SYMATTR Value2 l=50n w=500n
SYMBOL nmos4 320 56 R270
SYMATTR InstName M8
SYMATTR Value N_50n
SYMATTR Value2 l=50n w=500n