SP6644

® SP6644/6645 Single/Dual Alkaline Cell, High Efficiency Boost DC-DC Regulator ■ 90mA Output Current at 1.3V Input ■ 190mA Output Current at 2.6V Input ■ +2V to +5.5V Output Range ■ 0.88V Guaranteed Start-Up ■ 92% High Efficiency ■ 1.6µA Quiescent Supply Current at VBATT ■ Reverse Battery Protection ■ Internal Synchronous Rectifier ■ 5nA Logic Controlled Shutdown Current From VBATT ■ Low-Battery Detection Active LOW Output VBAT 1 BATTL0 2 RLIM 3 SHDN 4 SP6644 SP6645 8 Pin MSOP 8 V OUT 7 LX 6 GND 4 FB Now Available in Lead Free Packaging ■ Small 8 Pin MSOP Package ■ No External FETs ■ Flexibility to Optimize Inductor Type with Programmable Peak Current Control DESCRIPTION The SP6644/6645 devices are high-efficiency, low-power step-up DC-DC converters ideal for single or dual alkaline cell applications such as pagers, remote controls, pointing devices, medical monitors, and other low-power portable end products. Designers can control the SP6644 device with an active LOW shutdown input. The SP6644 device features an active low output for batteries below +1.0V. The SP6645 device features an active low output for batteries below +2.0V. Both devices contain a 0.8Ω synchronous rectifier, a 0.5Ω N-channel MOSFET power switch, an internal voltage reference, circuitry for pulsefrequency-modulation, and an under voltage comparator. The output voltage for the SP6644/6645 devices is preset to +3.3V + 4% or can be adjusted from +2V to +5.5V by manipulating two external resistors T...