REV. A

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a

ADP3820

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700

World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 1999

Lithium-Ion

Battery Charger

FUNCTIONAL BLOCK DIAGRAM

IS

GATE

SD

50mV

+

–

BIAS

ADP3820

GND

FEATURES

1% Total Accuracy

630

A Typical Quiescent Current

Shutdown Current: 1

A (Typical)

Stable with 10

F Load Capacitor

4.5 V to 15 V Input Operating Range

Integrated Reverse Leakage Protection

6-Lead SOT-23-6 and 8-Lead SO-8 Packages

Programmable Charge Current

–20 C to +85 C Ambient Temperature Range

Internal Gate-to-Source Protective Clamp

APPLICATIONS

Li-Ion Battery Chargers

Desktop Computers

Hand-Held Instruments

Cellular Telephones

Battery Operated Devices

GENERAL DESCRIPTION

The ADP3820 is a precision single cell Li-Ion battery charge

controller that can be used with an external Power PMOS de-

vice to form a two-chip, low cost, low dropout linear battery

charger. It is available in two voltage options to accommodate

Li-Ion batteries with coke or graphite anodes. The ADP3820’s

high accuracy (

±1%) low shutdown current (1 µA) and easy

charge current programming make this device especially attrac-

tive as a battery charge controller.

Charge current can be set by an external resistor. For example,

50 m

Ω of resistance can be used to set the charge current to

1 A. Additional features of this device include foldback current

limit, overload recovery, and a gate-to-source voltage clamp to

protect the external MOSFET. The proprietary circuit also

minimizes the reverse leakage current from the battery if the

input voltage of the charger is disconnected. This feature elimi-

nates the need for an external serial blocking diode.

The ADP3820 operates with a wide input voltage range from

4.5 V to 15 V. It is specified over the industrial temperature

range of –20

°C to +85°C and is available in the ultrasmall

6-lead surface mount SOT-23-6 and 8-lead SOIC packages.

C1

10 F

+

–

R1

10k

+5V

50m

22 F

Li-Ion

BATTERY

NDP6020P

GND

IS

GATE

SD

ADP3820-xx

Figure 1. Li-Ion Charger Application Circuit