FEATURES
DESCRIPTION
Performance is optimized for use in single Li-Ion battery cell applications. Unlike an LDO, dropout is avoided when the input is less than 4.4V. Instead, a charge pump is activated to provide voltage boost and the head-room needed for voltage regulation. Only two 2.2μF bucket capacitors are required to deliver the full output current. The charge pump provides a low EMI solution compared to inductive boost regulators. The 2x and 1.5x modes deliver current to the load in each of two phases. The 1x mode turns off the charge pump, delivering current through an LDO. When active, the charge pump provides low-ripple operation at 200kHz, which is typically less than 30mVpp at the output. The SC631 is capable of delivering 250mA continuous current, with peak current to 500mA. A 22μF output capacitor is used for decoupling the load and for smoothing mode transitions. Hysteresis is provided to prevent chatter between charge pump modes. The micro lead-frame package is both small and thermally efficient, measuring 2 x 2 x 0.6 (mm).
Semtech Corporation
