The LTC2446/LTC2447 4-terminal switching enables multiplexed ratiometric measurements. Four sets of selectable differential inputs coupled with four sets of differential reference inputs allow multiple RTDs, bridges and other sensors to be digitized by a single converter. A fifth differential reference input can be selected for any input channel not requiring ratiometric measurements (thermocouples, voltages, current sense, etc.). The flexible input multiplexer allows single-ended or differential inputs coupled with a slaved reference input or a universal reference input.