Maxim MAX8814, MAX8814ETA+ Datasheet

General Description

The MAX8814 intelligent, stand-alone constant-current,
constant-voltage (CCCV), thermally regulated linear
charger is designed for charging a single-cell lithium­ion (Li+) battery. The MAX8814 integrates the current­sense circuit, MOSFET pass element, thermal­regulation circuitry, and eliminates the reverse-blocking
Schottky diode to create the simplest and smallest
charging solution for handheld equipment.

The IC controls the charging sequence from the pre­qualification state through constant-current fast-charge
and the final constant voltage charge. Proprietary ther­mal-regulation circuitry limits the die temperature dur­ing fast-charging or when the IC is exposed to high
ambient temperatures, allowing maximum charging
current without damaging the IC.

The MAX8814 achieves high flexibility by providing an
adjustable fast-charge current through an external
resistor. Other features include an active-low control
input (EN) and an active-low input power-source detec­tion output (POK). The IC also features a booting assis­tant circuit that distinguishes input sources and battery
connection and provides an output signal (ABO) for
system booting.

The MAX8814 accepts an input supply range from

4.25V to 28V, but disables charging if the input voltage
exceeds +7V to protect against unqualified or faulty AC
adapters. The IC operates over the extended tempera­ture range (-40°C to +85°C) and is available in a com­pact 8-pin thermally enhanced TDFN 2mm x 2mm
package (0.8mm max height).

Applications

Cellular and Cordless Phones

Smartphones and PDAs

MP3 Players

Digital Still Cameras

USB Appliances

Charging Cradles and Docks

Bluetooth

®

Equipment

Features

o CCCV, Thermally Regulated Linear 1-Cell Li+

Battery Charger

o No External MOSFET, Reverse Blocking Diode, or

Current-Sense Resistor

o Programmable Fast-Charge Current (1A

RMS

max)

o Proprietary Die Temperature Regulation Control

(+115°C)

o 4.25V to 28V Input Voltage Range with Input OVP

Above +7V

o Charge-Current Monitor for Fuel Gauging (ISET)

o Low Dropout Voltage (300mV at 500mA)
o Input Power-Source Detection Output (POK),

Charge-Enable Input (EN)

o Soft-Start Limits Inrush Current

o Output for Autobooting (ABO)

o Tiny 2mm x 2mm, 8-Pin TDFN Package, 0.8mm

Height (max)

MAX8814

28V Linear Li+ Battery Charger with

Smart Autoboot Assistant

________________________________________________________________

Maxim Integrated Products

1

19-0994; Rev 0; 10/07

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

EVALUATION KIT

AVAILABLE

Ordering Information

IN

EN

ABI

ISET

GND

ABO

BATT

EP

ON

OFF

POK

SYSTEM
SUPPLY

2.2μF Li+

4.25V TO 28V

MAX8814

+

Typical Operating Circuit

PART

TEMP

RANGE

PIN­PACKAGE

PKG

CODE

TOP

MARK

MAX8814ETA+

-40°C to
+85°C

8 TDFN
2mm x 2mm

T822+2 ABI

Bluetooth is a registered trademark of Bluetooth SIG.

+

Denotes a lead-free and RoHS-compliant package.

Pin Configuration appears at end of data sheet.

MAX8814

28V Linear Li+ Battery Charger with
Smart Autoboot Assistant

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= 5V, V

BATT

= 4V, R

POK

= 1MΩ to BATT, EN = 0V, R

ISET

= 2.8kΩ to GND, C

BATT

= 2.2µF, TA= -40°C to +85°C, unless other-

wise noted. Typical values are at T

A

= +25°C.) (Note 1)

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.

IN to GND ...............................................................-0.3V to +30V

ABI, BATT, EN, POK to GND....................................-0.3V to +6V

ABO to GND............................................-0.3V to (V

BATT

+ 0.3V)

ISET to GND .............................................................-0.3V to +4V

IN to BATT Continuous Current .........................................1A

RMS

Continuous Power Dissipation (TA= +70°C)

8-Pin TDFN (derate 11.9mW/°C above +70°C)

(multilayer PCB) ........................................................953.5mW

BATT Short-Circuit Duration .......................................Continuous

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

Junction Temperature......................................................+150°C

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

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

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Voltage Range 028V

Input Operating Voltage Range 4.25 6.50 V

VIN rising 40

Power-OK Threshold

V

IN

- V

BATT

,

10mV hysteresis (typ)

V

IN

falling 30

mV

Overvoltage-Lockout Trip
Threshold

V

IN

rising, 100mV hysteresis (typ) 6.5 7 7.5 V

Constant-current charging mode (I

BATT

= 0A) 0.8 1.35

IC disabled (VEN = 5V) 0.23 0.50

TA = +25°C 0.021 0.065

IN Input Current

V

IN

= 4V,

V

BATT

= 4.2V

T

A

= +85°C 0.021

mA

VIN = 0 to 4V,
V

BATT

= 4.2V

110

BATT Input Current

IC disabled 3

µA

T

A

= 0°C to +85°C 4.179 4.200 4.221

Battery Regulation Voltage I

BATT

= 0A

T

A

= -40°C to +85°C 4.158 4.200 4.242

V

Minimum BATT Bypass
Capacitance

2.2 µF

T

A

= 0°C to +85°C 524 570 616

V

BATT

= 3.5V

T

A

= -40°C to +85°C 485 570 656

T

A

= 0°C to +85°C 89 107 125

Fast-Charge Current

V

BATT

= 3.5V,

R

ISET

= 14kΩ

T

A

= -40°C to +85°C 80 107 134

mA

Prequalification Charge Current

Percentage of the fast-charge current, V

BATT

= 2.2V,

T

A

= 0°C to +85°C

41015%

Die Temperature Regulation
Threshold

+115 °C

V

BATT

Prequalification Threshold

Voltage

V

BATT

rising, 100mV hysteresis (typ) 2.3 2.5 2.7 V

Current-Sense Amplifier Gain
(I

BATT

to I

ISET

)

I

BATT

= 570mA 877.2 µA/A

MAX8814

28V Linear Li+ Battery Charger with

Smart Autoboot Assistant

_______________________________________________________________________________________ 3

PARAMETER CONDITIONS MIN TYP MAX UNITS

Regulator Dropout Voltage
(V

IN

- V

BATT

)

V

BATT

= 4.1V, I

BATT

= 425mA 240 500 mV

EN Logic-Input Low Voltage 4.25V < VIN < 6.5V 0.4 V
EN Logic-Input High Voltage 4.25V < VIN < 6.5V 1.3 V

EN and ABI Internal Pulldown

Resistance

100 200 400 kΩ

ABI Logic-Input Low Voltage VIN = 0V 0.4 V

ABI Logic-Input High Voltage VIN = 0V 1.3 V

ABO Output Low Voltage I

ABO (SINK)

= 1mA 0.4 V

ABO Output High Voltage I

ABO (SOURCE)

= 1mA

V

BATT

-

0.4V

V

POK Output Low Voltage I

POK

= 5mA 0.4 V

TA = +25°C 0.001 1

POK Output High Leakage
Current

V

POK

= 5.5V

T

A

= +85°C 0.002

µA

ELECTRICAL CHARACTERISTICS (continued)

(VIN= 5V, V

BATT

= 4V, R

POK

= 1MΩ to BATT, EN = 0V, R

ISET

= 2.8kΩ to GND, C

BATT

= 2.2µF, TA= -40°C to +85°C, unless other-

wise noted. Typical values are at T

A

= +25°C.) (Note 1)

Note 1: Specifications are 100% production tested at TA= +25°C. Limits over the operating temperature range are guaranteed by

design and characterization.

Typical Operating Characteristics

(VIN= 5V, V

BATT

= 4V, R

POK

= 1MΩ to BATT, EN = 0V, R

ISET

= 2.8kΩ to GND, C

BATT

= 2.2µF, TA= -40°C to +85°C, unless other-

wise noted. Typical values are at T

A

= +25°C.)

0

0.3

0.2

0.1

0.5

0.4

0.9

0.8

0.7

0.6

1.0

0 4 8 1216202428

SUPPLY CURRENT

vs. VOLTAGE

MAX8814 toc01

INPUT VOLTAGE (V)

SUPPLY CURRENT (mA)

EN = 0V

0

100

200

300

400

500

600

700

800

0105 15202530

DISABLED MODE SUPPLY CURRENT

vs. INPUT VOLTAGE

MAX8814 toc02

INPUT VOLTAGE (V)

SUPPLY CURRENT (μA)

VEN = 5V

0

200

100

400

300

600

500

700

900

800

1000

0 1.0 1.5 2.00.5 2.5 3.0 3.5 4.0 4.5

CHARGE CURRENT

vs. BATTERY VOLTAGE

MAX8814 toc03

BATTERY VOLTAGE (V)

CHARGE CURRENT (mA)

MAX8814

28V Linear Li+ Battery Charger with
Smart Autoboot Assistant

4 _______________________________________________________________________________________

0

300

200

100

500

400

900

800

700

600

1000

0 4 8 12 16 20 24 28

CHARGE CURRENT

vs. INPUT VOLTAGE

MAX8814 toc04

INPUT VOLTAGE (V)

CHARGE CURRENT (mA)

0

300

200

100

400

500

600

700

800

900

1000

0 200100 300 400 500

CHARGE CURRENT vs. INPUT

VOLTAGE HEADROOM

MAX8814 toc05

VIN - V

BATT

(mV)

CHARGE CURRENT (mA)

V

BATT

= 4V

V

IN

RISING

40

μs/div

STARTUP INTO PRECHARGE

100mA/div

MAX8814 toc06

0A
5V/div

5V/div

5V/div

0V

0V

0V

I

BATT

V

IN

V

EN

V

POK

V

BATT

= 2V

100μs/div

SHUTDOWN

(FAST-CHARGE TO SHUTDOWN)

500mA/div

MAX8814 toc07

0A

0V

5V/div

5V/div

5V/div

0V

0V

I

BATT

V

IN

V

EN

V

POK

-1.0

-0.4

-0.6

-0.8

-0.2

0

0.2

0.4

0.6

0.8

1.0

-40 10-15 35 60 85

BATTERY REGULATION VOLTAGE

ACCURACY vs. AMBIENT TEMPERATURE

MAX8814 toc08

TEMPERATURE (°C)

BATTERY REGULATION VOLTAGE ACCURACY (%)

I

BATT

= 0A

CHARGE CURRENT vs. R

ISET

MAX8814 toc09

R

ISET

(kΩ)

CHARGE CURRENT (mA)

100010010

10

100

1000

1

1 10,000

0

200

100

400

300

600

500

700

-40 10-15 356085

CHARGE CURRENT vs. AMBIENT

TEMPERATURE

MAX8814 toc10

TEMPERATURE (°C)

CHARGE CURRENT (mA)

R

ISET

= 2.8kΩ

V

BATT

= 4V

V

BATT

= 3.2V

4μs/div

AUTOBOOT ENABLED

BY ABI SIGNAL

MAX8814 toc11

0V

0V

5V/div

5V/div

5V/div

5V/div

0V

0V

V

ABI

V

IN

V

BATT

V

ABO

4μs/div

AUTOBOOT ENABLED

BY INPUT SUPPLY

MAX8814 toc12

0V

5V/div

0V

5V/div

5V/div

5V/div

0V

0V

V

ABI

V

IN

V

BATT

V

ABO

Typical Operating Characteristics (continued)

(VIN= 5V, V

BATT

= 4V, R

POK

= 1MΩ to BATT, EN = 0V, R

ISET

= 2.8kΩ to GND, C

BATT

= 2.2µF, TA= -40°C to +85°C, unless other-

wise noted. Typical values are at T

A

= +25°C.)