19-4405; Rev 0; 3/09
28V Linear Li+ Battery Chargers with Battery
Detection and Overvoltage Protected Output
The MAX8845Z/MAX8845Y are intelligent, stand-alone
constant-current, constant-voltage (CCCV), thermally
regulated linear chargers designed for charging a sin-
gle-cell lithium-ion (Li+) battery. The MAX8845Z/
MAX8845Y integrate a current-sense circuit, MOSFET
pass element, thermal-regulation circuitry, and elimi-
nates the external reverse-blocking Schottky diode to
create the simplest and smallest charging solutions for
The ICs control 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 ICs are exposed to
high ambient temperatures, allowing maximum charg-
ing current without damaging the ICs.
The MAX8845Z/MAX8845Y achieve high flexibility
by providing adjustable fast-charge currents
(SETI) and an adjustable top-off current threshold
(MIN) through external resistors. The MAX8845Z/
MAX8845Y feature a booting assistant circuit that dis-
tinguishes input sources and battery connection and
provides an enable signal (ABO—MAX8845Z and
ABO—MAX8845Y) for system booting.
The MAX8845Z/MAX8845Y also integrate an overvolt-
age-protected output (SAFEOUT) for low voltage-rated
USB or charger inputs in system, and a battery-pack
detection circuit (DETBAT) that disables the charger
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 MAX8845Z/MAX8845Y accept an input supply
range from 4.25V to 28V, but disables charging if the
supply voltage exceeds +7.5V to protect against
unqualified or faulty AC adapters. The IC’s operate over
the extended temperature range (-40°C to +85°C) and
are available in a compact 12-pin, thermally enhanced
thin QFN, 3mm x 3mm package (0.8mm max height).
Cellular and Cordless Phones
Smart Phones and PDAs
Digital Still Cameras
Charging Cradles and Docks
♦ CCCV, Thermally Regulated Linear 1-Cell Li+
♦ No External MOSFET, Reverse Blocking Diode, or
♦ Programmable Fast-Charge Currents (1ARMS max)
♦ Programmable Top-Off Current Threshold (MIN)
♦ Input Overvoltage Protected 4.7V Output
♦ Proprietary Die Temperature Regulation Control
♦ 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
♦ Output for Autobooting (ABO—MAX8845Z,
♦ Tiny, 3mm x 3mm 12-Pin Thin QFN Package,
0.8mm Height (max)
MAX8845ZETC+ 12 Thin QFN-EP* ABL Active high
MAX8845YETC+ 12 Thin QFN-EP* ABM Active low
Note: All devices are specified over the -40°C to +85°C oper-
ating temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Typical Operating Circuit and Pin Configurations 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.