I need an instrument input amp with 1M input impedance and -0.5 gain, and very low phase shift out to 100 KHz.
I'm not sure what sorts of parasitic shunt capacitance I'll see on the resistors, theoretically 1M input and 500K feedback. My board stackup may affect the shunt capacitances some. Maybe if I use 2x500K instead of 1M, things will work out automatically.
Good news: my preferred opamp, AD8034, now has a model built-into LT Spice. So I'll buy more ADI parts because they acquired LTC and LT Spice.
Version 4 SHEET 1 880 680 WIRE -768 -128 -800 -128 WIRE -752 -128 -768 -128 WIRE -592 -128 -624 -128 WIRE -576 -128 -592 -128 WIRE -320 -128 -448 -128 WIRE -144 -128 -256 -128 WIRE -48 -128 -144 -128 WIRE 144 -128 16 -128 WIRE 304 -128 144 -128 WIRE 496 -128 368 -128 WIRE -800 -80 -800 -128 WIRE -624 -80 -624 -128 WIRE -800 48 -800 0 WIRE -624 48 -624 0 WIRE -448 48 -448 -128 WIRE -400 48 -448 48 WIRE -288 48 -400 48 WIRE -144 48 -144 -128 WIRE -144 48 -208 48 WIRE -80 48 -144 48 WIRE 144 48 144 -128 WIRE 144 48 0 48 WIRE 288 48 144 48 WIRE 496 48 496 -128 WIRE 496 48 368 48 WIRE -448 144 -448 48 WIRE 144 192 144 48 WIRE 176 192 144 192 WIRE 496 208 496 48 WIRE 496 208 240 208 WIRE 560 208 496 208 WIRE 592 208 560 208 WIRE 176 224 144 224 WIRE -448 320 -448 224 WIRE 144 352 144 224 FLAG 144 352 0 FLAG -448 320 0 FLAG -624 48 0 FLAG -800 48 0 FLAG -768 -128 +12 FLAG 208 176 +12 FLAG -592 -128 -12 FLAG 208 240 -12 FLAG -400 48 GEN FLAG 560 208 OUT SYMBOL res -96 64 R270 WINDOW 0 -45 60 VTop 2 WINDOW 3 -55 61 VBottom 2 SYMATTR InstName R1 SYMATTR Value 500K SYMBOL res 272 64 R270 WINDOW 0 -37 60 VTop 2 WINDOW 3 -41 61 VBottom 2 SYMATTR InstName R2 SYMATTR Value 500K SYMBOL voltage -448 128 R0 WINDOW 123 64 135 Left 2 WINDOW 39 0 0 Left 2 WINDOW 0 77 60 Left 2 WINDOW 3 35 99 Left 2 SYMATTR Value2 AC 1 SYMATTR InstName V1 SYMATTR Value SINE(0 1 1k) SYMBOL voltage -624 -96 R0 SYMATTR InstName V2 SYMATTR Value -15 SYMBOL voltage -800 -96 R0 SYMATTR InstName V3 SYMATTR Value 15 SYMBOL Opamps\\AD8034 208 144 R0 WINDOW 0 73 117 Left 2 WINDOW 3 43 152 Left 2 SYMATTR InstName U1 SYMBOL res -304 64 R270 WINDOW 0 -45 61 VTop 2 WINDOW 3 -55 59 VBottom 2 SYMATTR InstName R3 SYMATTR Value 500K SYMBOL cap -256 -144 R90 WINDOW 0 72 30 VBottom 2 WINDOW 3 79 30 VTop 2 SYMATTR InstName C2 SYMATTR Value {Cp} SYMBOL cap 16 -144 R90 WINDOW 0 72 30 VBottom 2 WINDOW 3 79 30 VTop 2 SYMATTR InstName C1 SYMATTR Value {Cp} SYMBOL cap 368 -144 R90 WINDOW 0 72 30 VBottom 2 WINDOW 3 79 30 VTop 2 SYMATTR InstName C3 SYMATTR Value {Cp} TEXT -808 216 Left 2 !.ac dec 100 100 1Meg TEXT -768 120 Left 2 ;P330 Input Amp TEXT -768 160 Left 2 ;JL May 5, 2018 TEXT -776 288 Left 2 !.param Cp=0.1p