Applications such as solid-state drives (SSDs), power fail alarms, and nonvolatile dual in-line memory modules (NVDIMMs) require reliable short-term uninterrupted power in the event of a main power failure. Linear Technology’s LTC3350 supercapacitor charger and backup controller IC incorporates all PowerPath control, capacitor stack charging and balancing, and capacitor “health” monitoring to become a reliable, standalone, capacitor-based backup-power solution. Input voltage ranges from 4.5 to 35 V, and there’s over 10 A of charge/backup current capability. Balancing and overvoltage protection is integrated for a series stack of one to four capacitors. A synchronous step-down controller dives N-channel MOSFETs for constant current/voltage charging of the capacitor stack at up to 5 V per cell. In backup mode, the step-down converter runs in reverse as a synchronous step-up dc-dc to deliver power from the supercap stack to the system supply that requires backup. A dual ideal diode controller uses N-channel MOSFETs for low-loss power paths from the input and supercaps to the backup system supply. A 14-bit analog-to-digital converter continuously monitors input and output voltage and current. Meanwhile, an internal measurement system monitors backup-capacitor parameters, such as capacitor stack voltage, capacitance, and stack equivalent series resistance (ESR).