In examples, a system includes a differential input device having a first input and a second input. The system includes a window generator configured to output, at a first output, a first voltage above a reference voltage and a second voltage, at a second output, below the reference voltage. The system includes a multiplexer coupled to the first output and the second output, the multiplexer configured to receive the first voltage, the second voltage, and an input voltage. The system includes a selector coupled to the multiplexer and configured to select the first voltage, the second voltage, or the input voltage based on a value of the input voltage, where the selector is configured to cause the multiplexer to provide the selected voltage to the first input of the differential input device, where a voltage source provides the reference voltage to the second input of the differential input device.