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Date: 11/30/04 SP6644/6645 High Efficiency Boost Regulator © Copyright 2004 Sipex Corporation
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 V
BATT
■ Reverse Battery Protection
■ Internal Synchronous Rectifier
■ 5nA Logic Controlled Shutdown Current
From V
BATT
■ Low-Battery Detection Active LOW Output
GND
FB
LX
V
BATT
47µF
47µF
R
LIM
+3.3V
OUT
SHDN
22µH
0.7A
0.88V to
3.3V Input
SP6644
SP6645
BATTLO
V
OUT
®
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 pulse-
frequency-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
TYPICAL APPLICATION CIRCUIT
SP6644
SP6645
8 Pin MSOP
8
7
6
4
V
OUT
LX
GND
FB
V
BAT
BATTL0
R
LIM
SHDN
1
2
3
4
Now Available in Lead Free Packaging
■ Small 8 Pin MSOP Package
■ No External FETs
■ Flexibility to Optimize Inductor Type
with Programmable Peak Current
Control
