SP6643

® SP6642/6643 Single Alkaline Cell, High Efficiency Step-Up DC-DC Converter s 20mA Output Current at 1.2V Input s +2V to +5.5V Output Range s 0.85V Guaranteed Start-Up s 83% High Efficiency s 1.5µA Quiescent Supply Current at V BATT s Reverse Battery Protection s Internal Synchronous Rectifier s 5nA Logic Controlled Shutdown Current From VBATT For The SP6642 s Low-Battery Detection Active LOW Output For The SP6643 s Extremely Small µSOIC Package s Pin-to-pin Compatible With MAX1642 And MAX1643 DESCRIPTION The SP6642/6643 devices are high-efficiency, low-power step-up DC-DC converters for +1V inputs ideal for single alkaline cell applications such as pagers, remote controls, and other low-power portable end products. Designers can control the SP6642 device with a 1nA active LOW shutdown input. The SP6643 features an active LOW output for low-battery conditions. Both devices contain a 0.8Ω synchronous rectifier, an oscillator, a 0.6Ω N-channel MOSFET power switch, an internal voltage reference, circuitry for pulse-frequency-modulation, and an under voltage comparator. The output voltage for the SP6642/6643 devices is preset to +3.3V + 4% or can be adjusted from +2V to +5.5V by manipulating two external resistors. VBATT 1 PFI 2 PFO 3 SHDN 4 SP6642 8 VOUT 7 LX 6 GND 5 FB VBATT 1 PFI 2 BATTLO 3 PFO 4 SP6643 8 VOUT 7 LX 6 GND 5 FB Rev. 10-6-00 SP6642/6643 High Efficiency Step-Up DC-DC Converter 1 © Copyright 2000 Sipex Corporation ABSOLUTE MAXIMUM RA...