Rainbow Electronics MAX8922L User Manual

General Description

The MAX8922L linear battery charger safely charges a
single-cell lithium-ion (Li+) battery. Charging rate is
optimized to accommodate the thermal characteristics
of a given application. There is no need to reduce the
maximum charge current at the worst-case charger
power dissipation. Charging is optimized for a single
Li+ cell using a control algorithm that includes low-bat­tery precharging, voltage and current-limited fast
charging, and top-off charging, while continuously
monitoring for input overvoltage and device die-temper­ature conditions. The fast-charge current and top-off
current thresholds are programmable by a simple
1-Wire®serial interface. The charger status and valid
input power are indicated by two open-drain outputs
(CHG and POK).

The fast-charge current is defaulted to 400mA and pro­grammable through the 1-Wire interface (EN/SET). The
MAX8922L also can be programmable to GSM test
mode through the 1-Wire interface.

The MAX8922L is available in a tiny (3mm x 2mm x

0.8mm) 10-pin TDFN package.

Applications

GSM/EDGE/UMTS/CDMA Cell Phones

Digital Cameras

PDAs

Portable Media Players and MP3 Players

Wireless Appliances

Features

o Overvoltage-Protected 30VDCRated Input (IN)

o Input Overvoltage-Protected Safe 4.94V LDO

Output

o 2.3A GSM RF Test Mode

o No External FET, Blocking Diode, or Sense

Resistor Required

o 1-Wire Easy Programmable Fast-Charge and GSM

Test Mode (EN/SET)

o Resistor-Programmable Fast-Charge Current

(SETI)

o Resistor-Programmable Top-Off Current

Threshold (MIN)

o Prequalification Charge
o Power-OK Monitor Output (POK)
o Charging-Status Output (CHG)

o Die Temperature Regulation for Optimized

Charge Rate

o Tiny (3mm x 2mm x 0.8mm) 10-Pin TDFN Package

MAX8922L

30V Li+ Linear Battery Charger

with GSM Test Mode in 3mm x 2mm TDFN

________________________________________________________________

Maxim Integrated Products

1

19-4929; Rev 0; 9/09

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.

Ordering Information

+

Denotes a lead(Pb)-free and RoHS-compliant package.

*

EP = Exposed pad.

Note: This device operates in the -40°C to +85°C extended
operating temperature range.

1-Wire is a registered trademark of Maxim Integrated Products, Inc.

Typical Operating Circuit

Pin Configuration

PART PIN-PACKAGE TOP MARK

MAX8922LETB+T 10 TDFN-EP* AWN

TOP VIEW

*EP = EXPOSED PAD.

BAT

1019283746

IN

(3mm x 2mm x 0.8mm)

CHG

POKSETI

MAX8922L

GND

TDFN

TEST

LDO

EN/SETMIN

*EP

5

USB/AC ADAPTER

4.45V TO 30V

IN

SETI

R

SETI

MAX8922L

MIN

R

MIN

EN\SET

EP

GND

TEST

BAT

LDO

SYSTEM SUPPLY

CHG

POK

MAX8922L

30V Li+ Linear Battery Charger
with GSM Test Mode in 3mm x 2mm TDFN

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= 5V, V

BAT

= 4V, V

EN/SET

= 0V, TA= -40°C to +85°C, typical values are at TA= +25°C, unless otherwise noted.) (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

BAT, CHG, EN/SET, POK, SETI,

MIN, LDO, TEST to GND ......................................-0.3V to +6V

Continuous Power Dissipation (T

A

= +70°C)
10-Pin (3mm x 2mm) TDFN

(derate 14.9mW/°C above +70°C)..........................1188.7mW

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

IN

Input Voltage Range 028V

Input Voltage Operating Range (Note 2) 4.45 7 V

Input Undervoltage Threshold
(UVLO)

Input Overvoltage Threshold
(OVP)

IN-to-BAT On-Resistance VIN = 4.15V, V

IN-to-BAT Comparator Threshold

BAT

BAT Regulation Voltage I

Battery Removal Detection
Threshold

Charging Current

Soft-Start Time Ramp time to fast-charge current 250 µs

BAT Precharge Threshold V

Precharge Current 80 mA

BAT Leakage Current VIN = 0V, V

PARAMETER CONDITIONS MIN TYP MAX UNITS

rising, 500mV hysteresis (typ) 3.80 3.90 4.00 V

V

IN

rising, 200mV hysteresis (typ) 7.2 7.5 7.8 V

V

IN

I

= 0mA, charge mode 700 1300

BAT

V

= 5V, standby mode 250 440Input Supply Current

EN/SET

= V

V

IN

VIN rising 120 250 500

V

IN

BAT

V

BAT

Hysteresis 0.2

Default fast-charge current, V
EN/SET = one pulse with low > 4ms, R

one-pulse mode, V

EN/SET = two pulses with low > 4ms, V

EN/SET = three pulses with low > 4ms,

V

BAT

BAT

, shutdown mode 200

BAT

= 4V 0.35 Ω

BAT

falling 100

= 100mA

rising 4.67

= 3.5V (Note 3)

rising, 300mV hysteresis (typ) 2.5 V

= 4.2V 1 5 µA

BAT

TA = +25°C 4.179 4.2 4.221

T

= 3.5V

BAT

= -40°C to +85°C 4.158 4.2 4.242

A

= 3.5V 365 400 435

BAT

= 3kΩ,

SETI

= 3.5V 80 90 100

BAT

460 500 540

2350

µA

mV

V

V

mA

MAX8922L

30V Li+ Linear Battery Charger

with GSM Test Mode in 3mm x 2mm TDFN

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VIN= 5V, V

BAT

= 4V, V

EN/SET

= 0V, TA= -40°C to +85°C, typical values are at TA= +25°C, unless otherwise noted.) (Note 1)

Note 1: Limits are 100% production tested at T

A

= +25°C. Limits over the operating temperature range are guaranteed by design

and characterization.

Note 2: Guaranteed by undervoltage- and overvoltage-threshold testing. If V

BAT

= 4.2V, VINneeds to be > 4.2V + 250mV (typ) to

start normal operation. After the MAX8922L turns on, it can operate until V

BAT

+ 100mV (typ). For complete charging, the

input voltage must be > 4.45V. See the

Input Sources

section.

Note 3: Used for factory GSM RF calibration. 217Hz, 12.5% current pulse, T

A

= +25°C. Not for continuous charge current.

Note 4: Not tested. Design guidance only.

LDO

Minimum LDO Bypass
Capacitance

LDO Regulated Output Voltage I

LDO Output-Current Limit 100 mA

EN/SET

Logic Input Thresholds

Program Lock Time 4ms

Shutdown Delay VIN = 5V, EN/SET from low to high 4 ms

t

LOW

t

HIGH

Pulldown Resistor 2MΩ

POK, CHG

Logic Output Voltage, Low I

Logic Output Current, High V

CHG

Top-Off Threshold

Detection Delay I

THERMAL LOOP

Thermal-Limit Temperature

Thermal-Limit Gain Reduction of I

PARAMETER CONDITIONS MIN TYP MAX UNITS

= 10mA, VIN = 5V 4.8 4.94 V

LDO

Rising 1.4

Falling 0.4

(Note 4) 100 1400

(Note 4) 100 1400

= I

POK,

POK

I

falling,

BAT

battery is
charged

falls below top-off threshold 2 4 6 ms

BAT

Junction temperature when the charge current is
reduced, T

= 5mA 0.05 0.2 V

CHG

= V

= 5.5V, VIN = 0V

CHG

rising

J

for increase of TJ, default mode -28 mA/°C

BAT

Default top-off threshold, hysteresis
(typ) = 80mA

EN/SET = one pulse, R

1.875kΩ, hysteresis (typ) = 130mA

EN/SET = two pulses, hysteresis
(typ) = 22mA

TA = +25°C 0.001 1

T

= +85°C 0.01

A

60 80 100

=

MIN

60 80 100

50 60 70

+105 °C

1µF

V

µs

µA

mA

MAX8922L

30V Li+ Linear Battery Charger
with GSM Test Mode in 3mm x 2mm TDFN

4 _______________________________________________________________________________________

Typical Operating Characteristics

(VIN= 5V, V

EN/SET

= 0V. V

BAT

= 4V, MAX8922L Evaluation Kit. TA= +25°C, unless otherwise noted.)

SUPPLY CURRENT vs.

SUPPLY VOLTAGE

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

SUPPLY CURRENT (mA)

0.2

0.1

0

07

SUPPLY VOLTAGE (V)

CHARGE CURRENT vs.

SUPPLY VOLTAGE

500

450

400

350

300

250

200

150

CHARGE CURRENT (mA)

100

50

0

030

SUPPLY VOLTAGE (V)

653 421

400mA DEFAULT
V

= 4V

BAT

272418 216 9 12 153

DISABLED SUPPLY CURRENT vs.

1.0

0.9

MAX8922 toc01

0.8

0.7

0.6

0.5

0.4

0.3

0.2

STANDBY SUPPLY CURRENT (mA)

0.1

0

07

CHARGE CURRENT WITH ONE

MAX8922 toc04

V

EN/SET

I

BAT

SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

EN/SET PULSE

1ms/div

653 421

MAX8922 toc05

MAX8922 toc02

5V/div

0

500mA

400mA

100mA/div

0

CHARGE CURRENT vs.

BATTERY VOLTAGE

600

500mA SETI MODE

500

400mA PRESET

400

300

200

CHARGE CURRENT (mA)

100

90mA PRESET

0

05

BATTERY VOLTAGE (V)

4321

MAX8922 toc03

CHARGE CURRENT WITH TWO

V

EN/SET

EN/SET PULSES

I

BAT

1ms/div

MAX8922 toc06

5V/div

0

400mA

100mA/div

0

GSM TRANSIENT RESPONSE

V

BAT

I

BAT

1ms/div

MAX8922 toc07

NO BATTERY
C

= 68µF

BAT

200mv/div
AC-COUPLED

1A/div

0A

800

700

600

500

400

300

CHARGE CURRENT (mA)

200

100

INPUT VOLTAGE HEADROOM

I

FAST-CHARGE

0

0 300

VIN - V

(mV)

BAT

CHARGE CURRENT vs.

MAX8922 toc08

= 677mA

25020050 100 150

MAX8922L

30V Li+ Linear Battery Charger

with GSM Test Mode in 3mm x 2mm TDFN

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

(VIN= 5V, V

EN/SET

= 0V. V

BAT

= 4V, MAX8922L Evaluation Kit. TA= +25°C, unless otherwise noted.)

Pin Description

BAT REGULATION VOLTAGE ACCURACY

1.0

0.8

0.6

0.4

0.2

0

-0.2

-0.4

REGULATION ACCURACY (%)

BAT

-0.6

V

-0.8

-1.0

-40 85

PIN NAME FUNCTION

1IN

2 SETI

3 GND Ground

4LDO

5MIN

6 EN/SET

7 TEST Factory Test Input. Connect to GND.

8 CHG

9 POK

10 BAT

— EP Exposed Pad. Connect to the GND plane for increased thermal dissipation.

vs. AMBIENT TEMPERATURE

VIN = 5V
NO BATTERY

AMBIENT TEMPERATURE (°C)

DC Input Supply. Connect IN to V
Bypass IN to GND with a 1µF or larger ceramic capacitor.

Charge-Current Program and Fast-Charge Current Monitor. Output current from SETI is 1000µA per
ampere of battery-charging current. Set the charging current by connecting a resistor (R

1) from SETI to GND. I

is not used.

4.94V Regulated LDO Output with Input Overvoltage Protection. Bypass LDO to GND with a 1µF or
larger ceramic capacitor. LDO can be used to supply low-voltage-rated USB systems.

Top-Off Current Threshold Programmable Input. I

(external SETI) is not used.

Active-Low Enable Input. EN/SET is used for programming fast-charge current and GSM test mode. For
detailed descriptions, see the Charger-Enable and Program Input (

Charging-Status Output. CHG is internally pulled low when the charger is in prequalification or fast-
charge mode. CHG is high impedance when the charger is in top-off or disabled.

Input Power-OK Monitor. POK is an open-drain output that is internally pulled low when V
than V
than V

Battery Connection. The IC delivers charging current and monitors battery voltage using BAT. Bypass
BAT to GND with a 2.2µF or larger ceramic capacitor. BAT is high impedance when the IC is disabled.

603510-15

and lower than V

UVLO

or greater than V

UVLO

600

MAX8922 toc09

500

400

300

200

CHARGE CURRENT (mA)

100

0

FAST-CHARGE

CHARGE CURRENT vs.

AMBIENT TEMPERATURE

400mA PRESET
VIN = 5V
V

= 4V

BATT

AMBIENT TEMPERATURE (°C)

> 4V and (VIN - V

IN

= 1500V/R

and VIN > V

OVP

or VIN < V

OVP

MAX8922 toc10

60

3510-15-40 85

) ≥ 250mV up to a 7V charging source.

BAT

. Connect to GND if pulse 1 mode (external SETI)

SETI

= 150V/R

MIN

+ 250mV. POK is high impedance when V

BAT

+ 100mV.

BAT

CHARGE CURRENT vs.

AMBIENT TEMPERATURE (1A CHARGE)

1000

900

800

700

600

500

400

300

CHARGE CURRENT (mA)

I

R

200

100

= 1.5k

SETI

V

= 5V

IN

V

= 4V

BATT

0

-40 85
AMBIENT TEMPERATURE (°C)

3510-15

SETI

Connect to GND if pulse 1 mode

MIN.

EN

/SET) section.

is greater

IN

60

in Figure

is less

IN

MAX8922 toc11