Version 4
SHEET 1 2268 680
WIRE 656 -176 240 -176
WIRE -864 -128 -1280 -128
WIRE 752 -64 720 -64
WIRE 848 -64 832 -64
WIRE 880 -64 848 -64
WIRE 1456 -64 960 -64
WIRE 720 -32 720 -64
WIRE 240 0 240 -176
WIRE 320 0 240 0
WIRE 320 16 320 0
WIRE 384 16 320 16
WIRE 496 32 448 32
WIRE -1280 48 -1280 -128
WIRE -1120 48 -1280 48
WIRE 384 48 320 48
WIRE -1120 64 -1120 48
WIRE -1072 64 -1120 64
WIRE -80 64 -144 64
WIRE 112 64 0 64
WIRE 320 64 320 48
WIRE 320 64 112 64
WIRE 496 64 496 32
WIRE 656 64 656 -176
WIRE 656 64 496 64
WIRE 848 64 848 -64
WIRE 1120 64 848 64
WIRE -976 80 -1008 80
WIRE 1120 80 1120 64
WIRE 1168 80 1120 80
WIRE -1072 96 -1120 96
WIRE -560 96 -560 80
WIRE -144 96 -144 64
WIRE 112 96 112 64
WIRE 1344 96 1232 96
WIRE -1360 112 -1360 96
WIRE -1120 112 -1120 96
WIRE -1120 112 -1360 112
WIRE -976 112 -976 80
WIRE -864 112 -864 -128
WIRE -864 112 -976 112
WIRE -752 112 -864 112
WIRE 1168 112 1120 112
WIRE -1360 128 -1360 112
WIRE 1120 128 1120 112
WIRE 1120 128 848 128
WIRE 1344 128 1344 96
WIRE 1456 128 1456 -64
WIRE 1456 128 1344 128
WIRE 1616 128 1456 128
WIRE 1744 128 1696 128
WIRE 1888 128 1744 128
WIRE -304 144 -304 112
WIRE -304 144 -384 144
WIRE 1744 160 1744 128
WIRE -384 176 -384 144
WIRE -304 176 -304 144
WIRE -560 192 -560 176
WIRE -144 208 -144 176
WIRE 112 208 112 176
WIRE 1744 256 1744 224
WIRE 656 272 656 64
WIRE 752 272 656 272
WIRE 848 272 848 128
WIRE 848 272 832 272
WIRE 880 272 848 272
FLAG -144 208 0
FLAG 112 208 0
FLAG -384 176 0
FLAG -304 32 vcc
FLAG -304 256 vee
FLAG -1360 16 vcc
FLAG -1360 208 0
FLAG -752 112 vref
FLAG 720 -32 0
FLAG 960 272 vref
FLAG -560 192 0
FLAG -560 80 vcc33
FLAG 1744 256 0
FLAG 1200 64 vcc33
FLAG 1200 128 0
FLAG -1040 48 vcc33
FLAG -1040 112 0
FLAG 416 0 vcc
FLAG 416 64 vee
SYMBOL res 16 48 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 9MEG
SYMBOL res 128 192 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R2
SYMATTR Value 1MEG
SYMBOL voltage -144 80 R0
WINDOW 123 24 124 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value2 AC 20
SYMATTR InstName V1
SYMATTR Value SINE(0 10 100)
SYMBOL voltage -304 16 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V3
SYMATTR Value 1.8
SYMBOL voltage -304 160 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V4
SYMATTR Value 1.8
SYMBOL res -1376 0 R0
SYMATTR InstName R3
SYMATTR Value 2.6k
SYMBOL res -1376 112 R0
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL res 848 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R5
SYMATTR Value 2k
SYMBOL res 976 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R6
SYMATTR Value 1k
SYMBOL res 848 -80 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R7
SYMATTR Value 2k
SYMBOL res 976 -80 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R8
SYMATTR Value 1k
SYMBOL voltage -560 80 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 3.3
SYMBOL res 1712 112 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R9
SYMATTR Value 10k
SYMBOL cap 1728 160 R0
SYMATTR InstName C1
SYMATTR Value 40p
SYMBOL Opamps\\UniversalOpamp2 1200 96 R0
SYMATTR InstName U1
SYMATTR Value2 Avol=1Meg GBW=2.8Meg Slew=10Meg
SYMBOL Opamps\\UniversalOpamp2 416 32 R0
SYMATTR InstName U2
SYMATTR Value2 Avol=1Meg GBW=2.8Meg Slew=10Meg
SYMBOL Opamps\\UniversalOpamp2 -1040 80 R0
SYMATTR InstName U3
SYMATTR Value2 Avol=1Meg GBW=2.8Meg Slew=10Meg
TEXT -40 360 Left 2 !.ac oct 50 1 1MEG
TEXT -1296 368 Left 2 ;Vref = (vcc-gnd)*R4/(R4+R3)\n       = (1.8 - 0)*(1k)/(1k+2.6k) = 0.5V
TEXT -456 -96 Left 2 ;+/- 1.8V Power Rails\nSupplied by LDO / Inverting Charge Pump\nNegative only needed for first buffer stage
TEXT -160 272 Left 2 ;V1 & R1 Model 10:1 O-Scope Probe
TEXT 192 -240 Left 2 ;1st Stage : Voltage Buffer\nBecause Level-Shifter has low input impedance
TEXT 1016 -168 Left 2 ;2nd Stage : Level Shifter\nShifting Centered at vref = 0.5V\nGain set by R5/R6 and R7/R8 = 1k/2k = 0.5
TEXT -1248 -168 Left 2 ;vref used to set DC offset of output
TEXT -768 256 Left 2 ;+3.3V Supply from PMOD Connector