1

®

FN9102.2

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

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ISL6291

Li-ion/Li Polymer Linear Battery Charger

The ISL6291 provides a low-cost integrated charger solution

for single-cell Li-ion and Li Polymer rechargeable batteries.

No external pass element, current sensing resistor, or

reverse blocking diode is required with this solution.

The ISL6291 is a constant-current (CC)/constant-voltage

(CV) charger. The constant charge current is programmable

up to 2.0A with an external signal resistor. An internal

trimmed current-sense circuit guarantees 10% accuracy,

with no bulky external current-sense resistor. The constant

voltage is either 4.1V or 4.2V. The charger always

preconditions the battery with 1/10 of the programmed

charge current at the beginning of a charge cycle, until it

verifies that the battery can be fast-charged. A safety timer

prevents over-charging a dead battery. The charging

terminates as the charge current falls below the

programmed minimum current during the CV mode. The

charger automatically re-charges the battery when the

battery voltage drops below a recharge threshold. A simple

interface with an NTC thermistor avoids charging the battery

outside a programmable temperature window. A thermal-

foldback feature of the ISL6291 guarantees safe operation

when the printed circuit board space is limited for thermal

dissipation. The charger reduces the charge current

automatically, as the internal temperature rises above a

preset level, to prevent further temperature rise.

When the wall adapter is not present, the ISL6291 draws

provide the charging status and fault information, and an

easy interface to system logic. A V2P8 pin outputs a 2.8V

reference voltage that can be used to bias other circuits, or

as an indication for the adapter presence.

The ISL6291 is packed in a thermally enhanced 5x5 QFN

package. See the Technical Brief TB389 given in the Related

Literature for more information related to the package.

Features

• Integrated Linear Pass Element

• Integrated Charge Current Sensor

• No External Reverse Blocking Diode Required

• 1% Voltage Accuracy

• Programmable Current Limit Up to 2.0A

• Programmable End-of-Charge Current

• Trickle Charge an Over Discharged Battery

• Charge Current Thermal Foldback

• Simple Interface for Low-Cost Thermistor

• Accepts USB Bus Power

• Ambient Temperature Range: -20°C to 70°C

• Thermally-Enhanced 5x5 QFN Package (

• Pb-Free Available (RoHS Compliant)

Applications

• Handheld Devices

• Cell Phones

•PDAs

• Stand-Alone Chargers

• USB Bus-Powered Chargers

Related Literature

• Technical Brief TB363 “Guidelines for Handling and

Processing Moisture Sensitive Surface Mount Devices

(SMDs)”

• Technical Brief TB389 “PCB Land Pattern Design and

Surface Mount Guidelines for QFN Packages”

Pinout

ISL6291 (QFN)

TOP VIEW

VIN

FAULT

STATUS

TIME

VBAT

TEMP

IMIN

IREF

1

3

4

15

16

14

13

2

12

10

9

11

6

57

8

Data Sheet

May 2, 2005