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Negative and positive voltages with LTC1403


Im new here and also electronics ;). I need to measure +/- 3.3V signal. I usually use microcontollers with level shifter but now I need some more precise ADC. I picked LTC1403. How can I measure negative voltages with differential input? Do I need level shifter and IN connect to ground? Or to minus of my of my power supply? Its my first time with external ADC.

Before signal I have some filters.

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  • The AD7980 is meant to be driven pseudo-differentially. The -input of the ADC will be grounded while the +input of the ADC is driven from ground to VREF. Using the ADA4945 to drive the AD7980 is possible if only one of the outputs is connected to the +input while the -input is grounded. The AD7915 is meant to be driven fully differentially and can be driven by both ADA4945 outputs which results in better SNR and THD performance. This extra performance is slightly more expensive.