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.

■ 20mA Output Current at 1.2V Input
■ +2V to +5.5V Output Range
■ 0.85V Guaranteed Start-Up
■ 83% High Efficiency
■ 1.5µA Quiescent Supply Current at VBATT
■ Reverse Battery Protection
■ Internal Synchronous Rectifier
■ 5nA Logic Controlled Shutdown Current From VBATT For The SP6642
■ Low-Battery Detection Active LOW Output For The SP6643
■ Extremely Small µSOIC Package
■ Pin-to-pin Compatible With MAX1642 And MAX1643