REV. 0

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a

ADP3801/ADP3802

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., 1998

High Frequency Switch Mode

Dual Li-Ion Battery Chargers

FUNCTIONAL BLOCK DIAGRAM

ADP3801/ADP3802

LDO +

REFERENCE

A/B

SELECT

MUX

DRV

VCC

CS+ CS–

A/B

PROG

ADJ

COMP

GND

SD

VL

RESET

ISET

BATB

BATA

EOC

SD\UVLO

GATE

DRIVE

CURRENT

LOOP

AMP + EOC

COMPARATOR

PWM

FINAL BATTERY

VOLTAGE

PROGRAM

(4.2, 8.4, 12.6)

VOLTAGE

LOOP

AMP

BATTERY

VOLTAGE

ADJUST

10%

SHUTDOWN

UVLO

+

RESET

FEATURES

Stand-Alone Li-Ion Battery Chargers

High End-of-Charge Voltage Accuracy

0.4% @ +25 C

0.75% @ –10 C to +70 C

Intelligent End-of-Charge Output Signal

Pin Programmable Cell Number Select

On Chip 3.3 V LDO Regulator

Programmable Charge Current with High Side Sense

Softstart Charge Current

Undervoltage Lockout

Drives External PMOS

10% Adjustable End-of-Charge Voltage

Charges NiCad, NiMH (with External

Controller)

PWM Oscillator Frequency:

ADP3801: 200 kHz

ADP3802: 500 kHz

APPLICATIONS

Fast Chargers

Universal Chargers

Cellular Phones

Portable Computers

Portable Instrumentation

Desktop Chargers

Personal Digital Assistants

GENERAL DESCRIPTION

The ADP3801 and ADP3802 are complete battery charging

ICs. The devices combine a high accuracy final battery voltage

control with a constant charge current control and an on-board

Low Drop-Out Regulator (LDO). The accuracy of the final

battery voltage control is guaranteed to

±0.75% to safely charge

Li-Ion batteries. An internal multiplexer allows the alternate

charging of two separate battery stacks. The final voltage is pin

programmable to one of three Li-Ion options: 4.2 V (one Li-Ion

cell), 8.4 V (two Li-Ion cells), or 12.6 V (three Li-Ion cells).

Paired with an external microcontroller for charge termination,

the ADP3801/ADP3802 works as a fast charger for NiCad/

NiMH batteries or as a universal charger for all three battery

chemistries. In addition, a pin is provided for changing the final

battery voltage by up to

±10% to adjust for variations in battery

chemistry from different Li-Ion manufacturers without loss of

accuracy in the final battery voltage.

BATA

BATB

VCC DRV

EOC

CS–

CS+

ISET

BATA

ADJ

GND

RESET

VL

ADP3801/ADP3802

SD

BATB

3.3V

40m

A/B

COMP

PROG

68 H

Figure 1. 4 Amp Dual Battery Charger