MAX8844Z Datasheet, PDF (1/17 Pages) Maxim Integrated Products – 28V Dual Input Linear Li+ Battery Chargers with Battery Detection and Overvoltage-Protected Output

19-4279; Rev 0; 3/09
EVALUATION KIT
AVAILABLE
28V Dual Input Linear Li+ Battery Chargers with
Battery Detection and Overvoltage-Protected Output
General Description
The MAX8844Z/MAX8844Y intelligent, stand-alone con-
stant-current, constant-voltage (CCCV), thermally regu-
lated dual input linear chargers are designed for
charging a single-cell lithium-ion (Li+) battery. The
MAX8844Z/MAX8844Y integrate a current-sense circuit,
MOSFET pass element, thermal-regulation circuitry,
and eliminate the external reverse-blocking Schottky
diode to create the simplest and smallest charging
solutions for handheld equipment.
The IC controls the charging sequence from the pre-
qualification state through constant current fast-charge,
top-off charge, and full-charge indication. 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 MAX8844Z/MAX8844Y achieve high flexibility by pro-
viding adjustable fast-charge currents (SETI) and an
adjustable top-off current threshold (MIN) through external
resistors. The IC features a booting assistant circuit that
distinguishes input sources and battery connection and
provides an enable signal (ABO, ABO) for system booting.
The ICs also integrate two input overvoltage-protected
LDO outputs (SAFEOUT, SAFEUSB) for low-voltage-
rated USB or charger inputs in system, and a battery
pack detection circuit (DETBAT) that disables the charg-
er when the battery pack is absent. Other features
include an active-low control input (EN), an active-low
input power source detection output (POK), and a fully
charged top-off threshold detection output (CHG).
The MAX8844Z/MAX8844Y automatically select between
either the USB or IN source. If both sources are present
at the same time, highest priority is given to the IN source.
The IN source is selected to ensure the shortest charging
time for the system since it is able to deliver the highest
current.
The MAX8844Z/MAX8844Y accept an input supply range
from 4.25V to 28V (IN and USB), but disable charging if
the input voltage exceeds +7.5V to protect against
unqualified or faulty AC adapters. The ICs operate over
the extended temperature range (-40°C to +85°C) and are
available in a compact 14-pin, thermally enhanced, lead-
free TDFN 3mm x 3mm package (0.8mm max height).
Applications
Cellular and Cordless
Phones
Smart Phones and PDAs
USB Appliances
Charging Cradles and
Docks
Digital Still Cameras
Bluetooth® Equipment
MP3 Players
Features
♦ CCCV, Thermally Regulated Linear One-Cell Li+
Battery Charger
♦ No External MOSFET, Reverse Blocking Diode, or
Current-Sense Resistor
♦ Programmable Fast-Charge Currents (1A_RMS max)
♦ Programmable Top-Off Current Threshold
♦ Input Overvoltage Protected 4.7V Output
(SAFEOUT) from IN
♦ Input Overvoltage Protected 4.7V Output
(SAFEUSB) from USB
♦ Proprietary Die Temperature Regulation Control
(+115°C)
♦ 4.25V to 28V Input Voltage Range with Input
Overvoltage Protection Above +7.5V
♦ Low-Dropout Voltage (300mV at 500mA)
♦ Input Power-Source Detection Output (POK),
Charge Status Output (CHG), Charge-Enable Input
(EN)
♦ Output for Autobooting (ABO, MAX8844Z)
♦ Output for Autobooting (ABO, MAX8844Y)
♦ Tiny 3mm x 3mm, 14-Pin TDFN Package, 0.8mm
Height (max)
Ordering Information
PART
PIN-
PACKAGE
TOP MARK
ABO
ACTIVE
STATE
MAX8844ZETD+ 14 TDFN-EP*
AEK
Active high
MAX8844YETD+ 14 TDFN-EP*
AEN
Active low
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Note: All devices are specified over the -40°C to +85°C oper-
ating temperature range.
Typical Operating Circuit and Pin Configuration appear at
end of data sheet.
Bluetooth is a registered trademark of Bluetooth SIG.
________________________________________________________________ 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.