SMB239
Programmable Linear Battery Charger in 1.3 x 2.1 uCSP
TM
FEATURES & APPLICATIONS
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World’s smallest linear charger
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Linear charging for reduced board space
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Up to 525mA charge current
Stable with small ceramic capacitors
INTRODUCTION
The SMB239 is a programmable single-cell lithium-ion/lithium-polymer
battery charger for a variety of portable applications. The device
provides a simple way to charge low- and medium-capacity Li-Ion or
Li-Polymer batteries via a USB port or an AC port. Unlike conventional
devices, the SMB239’s very small package and high level of
configurability simplify design in a wide range of handheld equipment.
Charge control includes qualification, trickle-charge, pre-charge,
constant current/constant voltage, and termination/safety settings that
are fully programmable via a serial I2C/SMBus making the device truly
a flexible solution. Pre-charge, fast charge and termination current
levels can be set via I2C commands. The SMB239 offers the option to
automatically recharge the battery upon power cycling, only when
battery voltage falls 220/390/550mV below the selectable float voltage.
This allows for a reduced number of charge/discharge cycles, thereby
extending battery life.
The SMB239 offers a wide variety of features that protect the battery
pack as well as the charger and input circuitry: over-current, under-
and over-voltage, and thermal protection. Ultra-precise, 1% accurate,
float voltage control improves battery capacity utilization. Status can
be monitored via the serial port for charge state and fault conditions.
In addition, one LED driver output can be used to signal charge status.
As a protection mechanism, when the junction temperature
approaches approximately 110°C, the SMB239 will start to reduce
charge current to ensure device and system reliability, while charging
the battery cell as fast as possible.
The SMB239 is available in a space-saving, 1.3mm x 2.1mm uCSP
TM
package with lead-free balls and is rated over the –30°C to +85°C
temperature range.
4.35 to 6.5V input voltage range
Small 1.3 x 2.1 uCSP
TM
package (0.5mm pitch)
High-accuracy output voltage regulation: 1%
Low reverse leakage current
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Digital programming of all major parameters via I
2
C
interface and lockable non-volatile memory
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Battery voltage set point
Pre-charge, fast charge, termination current
Fast charge voltage threshold
Temperature limits
Charge safety timers
Automatic restart threshold
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Fault/Status indicator
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Wide range of protection features
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Thermal regulation
Battery pack temperature monitor
Input/output over-voltage lockout
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Applications
Bluetooth & Stereo Headsets
Noise Cancellation Headphones
Wireless Handsets
MP3 Players
Wrist PDA/Watches
Handheld Equipment
SIMPLIFIED APPLICATIONS DRAWING
4.35V to 6.5V
10V Tolerance
IN
4.7uF
SMB239
OUT
BATT
Up to 525mA
Charge Current
Battery
OVLO
4.7uF
1-cell
Li+ Battery
RLIM
I2C Communication
SCL
SDA
GND
THERM
RED
LED
STAT
Figure 1 – Applications block diagram featuring the SMB239 programmable linear battery charger.
© SUMMIT
Microelectronics, Inc. 2005
• 757 N. Mary Avenue • Sunnyvale CA 94085 • Phone 408 523-1000 • FAX 408 523-1266
http://www.summitmicro.com/
2129 3.0 2/23/2009
1
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
