Conditioning high-voltage input signals to drive ADCs from high-voltage sources can be challenging. How can a highervoltage signal like ±10 V be attenuated and level-shifted to match the significantly lower differential and commonmode- voltage input required by the ADC? In this article, Part 1 of a three-part series, we consider a balanced, differential bipolar input signal and propose an architecture utilizing a fully differential operational amplifier (FDA) to accomplish the task.