Rainbow Electronics MAX1555 User Manual

General Description

The MAX1551/MAX1555 charge a single-cell lithium-ion
(Li+) battery from both USB* and AC adapter sources.
They operate with no external FETs or diodes, and
accept operating input voltages up to 7V.

On-chip thermal limiting simplifies PC board layout and
allows optimum charging rate without the thermal limits
imposed by worst-case battery and input voltage. When
the MAX1551/MAX1555 thermal limits are reached, the
chargers do not shut down, but progressively reduce
charging current.

The MAX1551 includes a POK output to indicate when
input power is present. If either charging source is
active, POK goes low. The MAX1555 instead features a
CHG output to indicate charging status.

With USB connected, but without DC power, charge cur­rent is set to 100mA (max). This allows charging from
both powered and unpowered USB hubs with no port
communication required. When DC power is connected,
charging current is set at 280mA (typ). No input-blocking
diodes are required to prevent battery drain.

The MAX1551/MAX1555 are available in 5-pin thin SOT23
packages and operate over a -40°C to +85°C range.

Applications

PDAs

Wireless Appliances

Cell Phones

Digital Cameras

Features

♦ Charge from USB or AC Adapter

♦ Automatic Switchover when AC Adapter is

Plugged In

♦ On-Chip Thermal Limiting Simplifies Board

Design

♦ Charge Status Indicator

♦ 5-Pin Thin SOT23 Package

♦ Protected by U.S. Patent #6,507,172

MAX1551/MAX1555

SOT23 Dual-Input USB/AC Adapter 1-Cell Li+

Battery Chargers

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-2902; Rev 0; 7/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Pin Configuration

MAX1551

(MAX1555)

DC

USB

BAT

AC ADAPTER

3.7V TO 7V

USB

3.7V TO 6V

TO SYSTEM
LOAD

Li+

GND

TO LOGIC RAIL

CHARGE

CONTROL

POK

(CHG)

LOGIC

CONTROL

Typical Operating Circuit

*Protected by U.S. Patent #6,507,172.

Selector Guide

PART TEMP RANGE PIN-PACKAGE

MAX1551EZK-T -40°C to +85°C 5 Thin SOT23-5

MAX1555EZK-T -40°C to +85°C 5 Thin SOT23-5

PART TOP MARK FEATURES

MAX1551EZK ADRT POK Output
MAX1555EZK ADRU CHG Output

TOP VIEW

15BATUSB

MAX1551

2

GND

POK

(CHG)

(MAX1555)

34

THIN SOT23

DC

MAX1551/MAX1555

SOT23 Dual-Input USB/AC Adapter 1-Cell Li+
Battery Chargers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDC= 5V, V

USB

= 0, I

BAT

= 0, C

BAT

= 1µF, TA = 0°C to +85°C, unless otherwise noted.)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

DC to GND......................................................................0 to +8V

DC to BAT .......................................................................0 to +7V

BAT, CHG, POK, USB to GND .................................-0.3V to +7V

Continuous Power Dissipation (T

A

= +70°C)

5-Pin Thin SOT23 (derate 9.1mW/°C above +70°C)....727mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature Range ............................-40°C to +150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

DC

DC Voltage Range (Note 1) 3.7 7.0 V

DC to BAT Voltage Range 0.1 6.0 V

DC Undervoltage Lockout
Threshold

DC Supply Current 1.75 3 mA

DC to BAT On-Resistance VDC = 3.7V, V

DC to BAT Dropout Voltage

USB

USB Voltage Range (Note 1) 3.7 6.0 V

USB Undervoltage Threshold

USB Supply Current V
USB to BAT On-Resistance V

USB to BAT Dropout Voltage

BAT

BAT Regulation Voltage VDC or V

DC Charging Current V

USB Charging Current V

BAT Prequal Threshold V

Prequalification Charging Current V

BAT Leakage Current VDC = V

POK, CHG, AND THERMAL LIMIT

CHG Threshold

CHG, POK Logic-Low Output I
CHG, POK Leakage Current V

Thermal-Limit Temperature

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input rising, 430mV hysteresis, V

= 3.6V 1 2 Ω

BAT

When charging stops, V
DC falling, 200mV hysteresis

Input rising, 430mV hysteresis, V
V

= 3V (Note 1)

BAT

= 5V, VDC = 0 1.65 3 mA

USB

= 3.7V, V

USB

When charging stops, V
USB falling, 200mV hysteresis, V

= 3.3V, V

BAT

= 3.3V, VDC = 0, V

BAT

rising, 100mV hysteresis 2.9 3 3.1 V

BAT

= 2.8V 20 40 80 mA

BAT

Charge current where CHG goes high,
I

falling, 50mA hysteresis

BAT

, I

CHG

POK

, V

CHG

Charge current reduced by 17mA/°C above this
temperature

BAT

= 5V 4.158 4.2 4.242 V

USB

USB

= 0, V

USB

= 10mA 150 300 mV

= 6V, TA = +25°C 0.001 1 µA

POK

BAT

= 3.6V, VDC = 0 2 4 Ω

BAT

= 0, VDC = 5V 220 280 340 mA

USB

= 4.2V 5 µA

BAT

= 3V (Note 1) 3.75 3.95 4.15 V

BAT

= 4V,

= 0,

DC

= 4V,

= 0

DC

= 5V 80 90 100 mA

30 60 90 mV

3.75 3.95 4.15 V

30 60 90 mV

25 50 100 mA

+110 °C

MAX1551/MAX1555

SOT23 Dual-Input USB/AC Adapter 1-Cell Li+

Battery Chargers

_______________________________________________________________________________________ 3

Note 1: The input undervoltage lockout has 430mV of hysteresis. The charger turns on when an input rises to 3.95V (typ), and turns

off when it falls below 3.52V.

Note 2: Specifications to -40°C are guaranteed by design, not production tested.

ELECTRICAL CHARACTERISTICS

(VDC= 5V, V

USB

= 0, I

BAT

= 0, C

BAT

= 1µF, TA = -40°C to +85°C, unless otherwise noted.) (Note 2)

DC

DC Voltage Range (Note 1) 3.7 7.0 V

DC to BAT Voltage Range 0.1 6.0 V

DC Undervoltage Lockout
Threshold

DC Supply Current 3mA

DC to BAT On-Resistance VDC = 3.7V, V

DC to BAT Dropout Voltage

USB

USB Voltage Range (Note 1) 3.7 6.0 V

USB Undervoltage Lockout
Threshold

USB Supply Current V

USB to BAT On-Resistance V

USB to BAT Dropout Voltage

BAT

BAT Regulation Voltage VDC or V

DC Charging Current V

USB Charging Current V

BAT Prequal Threshold V

Prequalification Charging Current V

BAT Leakage Current VDC = V

POK, CHG

CHG Threshold

CHG, POK Logic-Low Output I
CHG, POK Leakage Current V

PARAMETER CONDITIONS MIN MAX UNITS

Input rising, 430mV hysteresis, V

= 3.6V 2 Ω

BAT

When charging stops, V
hysteresis

Input rising, 430mV hysteresis, VDC = 0, V
(Note 1)

= 5V, VDC = 0 3 mA

USB

= 3.7V, V

USB

When charging stops, V
hysteresis, V

USB

= 3.3V, V

BAT

= 3.3V, VDC = 0, V

BAT

rising, 100mV hysteresis 2.9 3.1 V

BAT

= 2.8V 20 80 mA

BAT

USB

Charge current where CHG goes high,

falling, 50mA hysteresis

I

BAT

, I

CHG

POK

, V

CHG

POK

= 3.6V, VDC = 0 4 Ω

BAT

= 0

DC

= 5V 4.141 4.259 V

= 0, VDC = 5V 220 340 mA

USB

= 0, V

BAT

= 10mA 300 mV

= 6V, T

= 4V, DC falling, 200mV

BAT

= 4V, USB falling, 200mV

BAT

= 5V 80 100 mA

USB

= 4.2V 5 µA

= +25°C1µA

A

= 3V (Note 1) 3.75 4.15 V

BAT

= 3V

BAT

30 95 mV

3.75 4.15 V

30 95 mV

25 100 mA