SMB139

http://www.summitmicro.com/

2121 3.0 6/19/2008

1

INTRODUCTION

• World’s smallest linear charger

•

Linear charging for reduced board space

o

Up to 210mA charge current *

o

Stable with small ceramic capacitors

• 4.35 to 6.5V input voltage range

• High-accuracy output voltage regulation: 1%

• Low reverse leakage current

interface and lockable non-volatile memory

o

Battery voltage set point

o

Pre-charge, fast charge, termination current

o

Fast charge voltage threshold

o

Temperature limits

o

Charge safety timers

o

Automatic restart threshold

• Fault/Status indicator

• Wide range of protection features

o

Thermal regulation

o

Input/output over-voltage lockout

Applications

• Bluetooth & Stereo Headsets

• Noise Cancellation Headphones

• MP3 Players

• Wrist PDA/Watches

• Toys

• Handheld Equipment

The SMB139 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-capacity Li-Ion or Li-Polymer

batteries via a USB port or an AC port. Unlike conventional devices,

the SMB139’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 Enable (EN) pin is used for

suspending or re-staring the charging process.

The SMB139 offers a wide variety of features that protect the battery

pack as well as the charger and input circuitry: over-current,

under/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 SMB139 will start to reduce

charge current to ensure device and system reliability, while charging

the battery cell as fast as possible.

The SMB139 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.

Figure 1 – Applications block diagram featuring the SMB139 programmable linear battery charger.

SIMPLIFIED APPLICATIONS DRAWING

FEATURES & APPLICATIONS

* Contact factory for higher current version

4.35V to 6.5V

10V Tolerance

IN

GND

STAT

RLIM

RED

LED

OUT

THERM

EN

1-cell

Li+ Battery

SDA

BATT

VDDCAP

1

µF

2.2

µF

SCL

2.2µF

SMB139

TRICKLE

SENSE

Up to 210mA

Charge Current

Battery

OVLO

I2C Communication

(Optional)

CHGSET

Optional