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I have a differential signal ±6 V (12 V differential) that I need to condition for an ADC (AD7124) with a 4.096 V reference voltage. Signals of interest are DC-20 kHz.

I can make the circuit below with one additional differential amplifier using the Analog Devices DiffAmpCalc software, however the gain on the amplifier has to be 0.3.

I've always avoided having gains less than 1 in circuits, but I assume (perhaps incorrectly) the DiffAmpCalc software would alert to an issue with this.

So can this work? Or do I need an additional high-impedance buffer with a voltage divider at the input to bring the signals down before running through the differential ADC driver?

enter image description here

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There is a 0.5 attenuation from loading the source impedance Rs and then a gain of 0.6 (0.597) in the differential amplifier itself, giving you about 0.3 overall.

If you're happy with that input impedance you appear to be done. If your source impedance is something other than the 150 ohms shown the gain will be higher or lower.

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