1

Rev. 3/5/02,

*Patent Pending

SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23

© Copyright 2002 Sipex Corporation

DESCRIPTION

The SP6641 is an ultra-low quiescent current, high efficiency, DC-DC boost converter designed

for single and dual cell alkaline, or Li-ion battery applications found in PDA’s, MP3 players, and

other handheld portable devices. The SP6641 features a 10

µA quiescent current, a 0.3Ω N-

channel charging switch, 0.9V input startup, and a 0.33A or 1.0A inductor current limiting feature.

The SP6641 is offered in a 5 pin SOT-23 package and provides an extremely small power supply

footprint optimized for portable applications. The SP6641 is preset to 3.3V and can be controlled

by a 1nA active LOW shutdown pin.

500mA Alkaline DC/DC Boost Regulator in SOT-23

®

s Ultra Low Quiescent Current: 10

µA

s Wide Input Voltage Range: 0.9V to 4.5V

s Fixed 3.3V or 5.0V Output Voltage

s Up to 87% Efficiency

s 0.3

s Startup Voltage Guaranteed at 0.9V

s 0.33A Inductor Current Limit (SP6641A)

s 1A Inductor Current Limit (SP6641B)

s Logic Shutdown Control

s SOT-23-5 Package

GND

SHDN

LX

SP6641

5 Pin SOT-23

1

2

3

5

4

APPLICATIONS

s PDA's

s DSC's

s CD/MP3 Players

s Pagers

s Digital Cameras

s Portable Handheld Medical Devices

SP6641A/6641B

Figure 1. Typical Application Schematic

Figure 2. Maximum Load Current in Operation

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

SP6641B, 1.0A, 3.3V

SP6641B, 1.0A, 5V

SP6641A, 0.33A, 3.3V

SP6641A, 0.33A, 5V

GND

LX

SHDN

L1

0.9V to 4.5V

U1

SP6641A

SHDN

®

®

C2

+3.3V or 5V

D1

1

2

3

C1

5

4

C3

R1

SP6641A 3.3V & 5V: C1 = C2 = 22

µF Ceramic, L1 = 22µH CDRH5D28,

D1 = MBR0520, C3 = Open, R1 = Shorted.

SP6641B 3.3V & 5V: C1 = C2 = 100

µF POSCAP, L1 = 10µH CDRH5D28,

D1 = ZHCS2000, C3 = 1

µF Ceramic, R1 = 10Ω.