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19-0994; Rev 0; 10/07
EVAALVUAAILTAIOBNLEKIT
28V Linear Li+ Battery Charger with
Smart Autoboot Assistant
www.datasheet4u.com
General Description
The MAX8814 intelligent, stand-alone constant-current,
constant-voltage (CCCV), thermally regulated linear
charger is designed for charging a single-cell lithium-
ion (Li+) battery. The MAX8814 integrates the current-
sense circuit, MOSFET pass element, thermal-
regulation 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 pre-
qualification state through constant-current fast-charge
and the final constant voltage charge. Proprietary ther-
mal-regulation circuitry limits the die temperature dur-
ing 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 detec-
tion output (POK). The IC also features a booting assis-
tant 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 tempera-
ture range (-40°C to +85°C) and is available in a com-
pact 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 (1ARMS 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)
Ordering Information
PART
TEMP PIN-
RANGE PACKAGE
PKG TOP
CODE MARK
MAX8814ETA+
-40°C to
+85°C
8 TDFN
2mm x 2mm
T822+2
+Denotes a lead-free and RoHS-compliant package.
ABI
Typical Operating Circuit
4.25V TO 28V
IN
BATT +
2.2μF
Li+
OFF
ON
MAX8814
EN
ABI
SYSTEM
SUPPLY
ISET
GND
POK
EP ABO
Bluetooth is a registered trademark of Bluetooth SIG.
Pin Configuration appears at end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
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.

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28V Linear Li+ Battery Charger with
Smart Autoboot Assistant
www.daAtasBheSeOt4uL.cUomTE MAXIMUM RATINGS
IN to GND ...............................................................-0.3V to +30V
ABI, BATT, EN, POK to GND....................................-0.3V to +6V
ABO to GND............................................-0.3V to (VBATT + 0.3V)
ISET to GND .............................................................-0.3V to +4V
IN to BATT Continuous Current .........................................1ARMS
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
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.
ELECTRICAL CHARACTERISTICS
(VIN = 5V, VBATT = 4V, RPOK = 1MΩ to BATT, EN = 0V, RISET = 2.8kΩ to GND, CBATT = 2.2µF, TA = -40°C to +85°C, unless other-
wise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
Input Voltage Range
Input Operating Voltage Range
Power-OK Threshold
Overvoltage-Lockout Trip
Threshold
IN Input Current
BATT Input Current
Battery Regulation Voltage
Minimum BATT Bypass
Capacitance
Fast-Charge Current
Prequalification Charge Current
Die Temperature Regulation
Threshold
CONDITIONS
VIN - VBATT,
10mV hysteresis (typ)
VIN rising
VIN falling
VIN rising, 100mV hysteresis (typ)
Constant-current charging mode (IBATT = 0A)
IC disabled (VEN = 5V)
VIN = 4V,
VBATT = 4.2V
TA = +25°C
TA = +85°C
VIN = 0 to 4V,
VBATT = 4.2V
IC disabled
IBATT = 0A
TA = 0°C to +85°C
TA = -40°C to +85°C
VBATT = 3.5V
TA = 0°C to +85°C
TA = -40°C to +85°C
VBATT = 3.5V,
RISET = 14kΩ
TA = 0°C to +85°C
TA = -40°C to +85°C
Percentage of the fast-charge current, VBATT = 2.2V,
TA = 0°C to +85°C
MIN TYP MAX UNITS
0 28 V
4.25 6.50 V
40
mV
30
6.5 7 7.5 V
0.8
0.23
0.021
0.021
1.35
0.50
0.065
mA
1 10
4.179
4.158
3
4.200
4.200
4.221
4.242
µA
V
2.2 µF
524 570 616
485 570 656
89 107 125
80 107 134
mA
4 10 15 %
+115
°C
VBATT Prequalification Threshold
Voltage
VBATT rising, 100mV hysteresis (typ)
2.3 2.5 2.7
V
Current-Sense Amplifier Gain
(IBATT to IISET)
IBATT = 570mA
877.2
µA/A
2 _______________________________________________________________________________________

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28V Linear Li+ Battery Charger with
Smart Autoboot Assistant
www.daEtaLshEeeCt4Tu.RcoImCAL CHARACTERISTICS (continued)
(VIN = 5V, VBATT = 4V, RPOK = 1MΩ to BATT, EN = 0V, RISET = 2.8kΩ to GND, CBATT = 2.2µF, TA = -40°C to +85°C, unless other-
wise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Regulator Dropout Voltage
(VIN - VBATT )
EN Logic-Input Low Voltage
EN Logic-Input High Voltage
EN and ABI Internal Pulldown
Resistance
VBATT = 4.1V, IBATT = 425mA
4.25V < VIN < 6.5V
4.25V < VIN < 6.5V
240 500
0.4
1.3
100 200 400
mV
V
V
kΩ
ABI Logic-Input Low Voltage
ABI Logic-Input High Voltage
ABO Output Low Voltage
VIN = 0V
VIN = 0V
IABO (SINK) = 1mA
0.4 V
1.3 V
0.4 V
ABO Output High Voltage
POK Output Low Voltage
POK Output High Leakage
Current
IABO (SOURCE) = 1mA
IPOK = 5mA
VPOK = 5.5V
TA = +25°C
TA = +85°C
VBATT -
0.4V
0.001
0.002
0.4
1
V
V
µA
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, VBATT = 4V, RPOK = 1MΩ to BATT, EN = 0V, RISET = 2.8kΩ to GND, CBATT = 2.2µF, TA = -40°C to +85°C, unless other-
wise noted. Typical values are at TA = +25°C.)
SUPPLY CURRENT
vs. VOLTAGE
1.0
EN = 0V
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0 4 8 12 16 20 24 28
INPUT VOLTAGE (V)
DISABLED MODE SUPPLY CURRENT
vs. INPUT VOLTAGE
800
VEN = 5V
700
600
500
400
300
200
100
0
0 5 10 15 20 25 30
INPUT VOLTAGE (V)
CHARGE CURRENT
vs. BATTERY VOLTAGE
1000
900
800
700
600
500
400
300
200
100
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
BATTERY VOLTAGE (V)
_______________________________________________________________________________________ 3

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28V Linear Li+ Battery Charger with
Smart Autoboot Assistant
www.datasheet4u.com
Typical Operating Characteristics (continued)
(VIN = 5V, VBATT = 4V, RPOK = 1MΩ to BATT, EN = 0V, RISET = 2.8kΩ to GND, CBATT = 2.2µF, TA = -40°C to +85°C, unless other-
wise noted. Typical values are at TA = +25°C.)
1000
900
800
700
600
500
400
300
200
100
0
0
CHARGE CURRENT
vs. INPUT VOLTAGE
4 8 12 16 20 24 28
INPUT VOLTAGE (V)
SHUTDOWN
(FAST-CHARGE TO SHUTDOWN)
MAX8814 toc07
IBATT 500mA/div
0A
VIN 5V/div
0V
5V/div
VEN 0V
5V/div
VPOK
0V
100μs/div
CHARGE CURRENT vs. AMBIENT
TEMPERATURE
700
VBATT = 4V
600
500
VBATT = 3.2V
400
300
200
100
0
-40
RISET = 2.8kΩ
-15 10 35 60
TEMPERATURE (°C)
85
1000
900
800
700
600
500
400
300
200
100
0
0
CHARGE CURRENT vs. INPUT
VOLTAGE HEADROOM
VBATT = 4V
VIN RISING
100 200 300 400
VIN - VBATT (mV)
500
BATTERY REGULATION VOLTAGE
ACCURACY vs. AMBIENT TEMPERATURE
1.0
0.8 IBATT = 0A
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
-40
-15 10 35 60
TEMPERATURE (°C)
85
AUTOBOOT ENABLED
BY ABI SIGNAL
MAX8814 toc11
STARTUP INTO PRECHARGE
MAX8814 toc06
VBATT = 2V
100mA/div
IBATT
0A
5V/div
VIN 0V
VEN 5V/div
0V
5V/div
VPOK
0V
40μs/div
CHARGE CURRENT vs. RISET
1000
100
10
1
1 10 100 1000 10,000
RISET (kΩ)
AUTOBOOT ENABLED
BY INPUT SUPPLY
MAX8814 toc12
VABI
VIN
VBATT
VABO
4μs/div
5V/div
0V VABI
5V/div
0V VIN
5V/div VBATT
0V
5V/div
0V VABO
4μs/div
5V/div
0V
5V/div
0V
5V/div
0V
5V/div
0V
4 _______________________________________________________________________________________

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28V Linear Li+ Battery Charger with
Smart Autoboot Assistant
www.datasheet4u.com
PIN
1
2
3
4
5
6
7
8
NAME
IN
GND
ISET
ABI
ABO
EN
POK
BATT
EP
Pin Description
FUNCTION
Input Supply Voltage. Bypass IN to GND with a 1µF or larger ceramic capacitor to minimize line noise
and maximize input transient rejection.
Ground. Connect GND and the exposed paddle to a large copper ground plane for maximum power
dissipation. Connect GND to the exposed paddle directly under the IC.
Charge-Current Program and Fast-Charge Current Monitor. Output current from ISET is 877.2µA per
ampere of battery charging current. Set the charging current by connecting a resistor (R2 in Figure 3)
from ISET to GND. IFAST-CHARGE = 1596V / RISET. To configure the MAX8814 as a USB charger, see
Figure 4.
Autobooting External Input. See the Autobooting Assistant section and Table 1 for autobooting
conditions. ABI is pulled to GND through an internal 200kΩ resistor.
Autobooting Logic Output. See the Autobooting Assistant section and Table 1 for autobooting
conditions.
Logic-Level Enable Input. Drive EN high to disable charger. Drive EN low or leave unconnected for
normal operation. EN has an internal 200kΩ pulldown resistor.
Input-Voltage Status Indicator. Connect a 1MΩ pullup resistor from POK to an external system supply.
POK is an open-drain output that asserts low when VIN > 4.25V and (VIN - VBATT) 40mV. If VBATT
(VIN - 40mV), the IC is shut down and POK becomes high impedance.
Battery Connection. Bypass BATT to GND with a minimum of 2.2µF of capacitor.
Exposed Paddle. Connect the exposed paddle to a large ground plane for maximum power
dissipation. Connect GND to the exposed paddle directly under the IC.
_______________________________________________________________________________________ 5