Si32297 dual-channel ProSLIC subscriber line interface circuit (SLIC) devices support up to 55 Vrms + 48 Vdc offset and 5 REN load with the lowest BOM cost using patented 7.6 W low-cost capacitive ultra-boost dc-dc tracking controllers. Low-cost inductors with capacitance boost dc-dc replaces transformer based flyback dc-dc designs often used in 7.6 W cable applications. Power efficiency is improved with patented low-power ringing (LPR) and energy-friendly smart ringing that can save power adapter cost in two channel applications.