The LTC3625 and LTC3625-1 are the latest in a family of 2-cell supercapacitor chargers for addressing high peak power, data backup and “dying gasp” needs in portable and data storage applications. The LTC3625’s high efficiency switchmode topology includes an internal buck converter between V_IN and the series capacitor mid-point V_MID to regulate the voltage on the bottom capacitor, as well as an internal boost converter between V_MID and V_OUT to regulate the voltage across the top capacitor. The devices can charge two supercapacitors in series from a 2.7V to 5.5V current-limited supply to a pin-selectable output voltage, that being 4.8V/5.3V for LTC3625 or 4V/4.5V for LTC3625-1. These ICs are optimized to provide fast capacitor charge times with high efficiency. The combination of high efficiency, high charge current, low quiescent current and low minimum external parts count make the LTC3625 ideal for small form factor backup or high peak power systems, USB-powered equipment, industrial PDAs, portable instruments and monitoring equipment, power meters, supercap backup circuits and PC card/USB modems.