SP6644
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 parator. 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
TYPICAL APPLICATION CIRCUIT
0.88V to 3.3V Input
47µF
22µH 0.7A
VBATT
RLIM
VOUT
SP6644 SP6645
SHDN
47µF
+3.3VOUT
BATTLO
Date: 11/30/04
SP6644/6645 High...
