General Description
The MAX8856 complete 1-cell Li+ battery charge-man-
agement IC operates from either a USB port or AC
adapter. It integrates a battery disconnect switch, cur-
rent-sense circuit, PMOS pass element, and thermal-
regulation circuitry, while eliminating the external
reverse-blocking Schottky diode, to create a simple
and small charging solution. The charging sequence
initiates from power-OK indication, through prequalifi-
cation, fast-charge, top-off charge, and finally charg-
ing-complete indication for single-cell Li+ batteries.
Charging is controlled using constant current, constant
voltage, or constant die-temperature (CCCVCT
J
) regu-
lation for safe operation in handhelds.
Two logic inputs (EN1, EN2) select suspend mode,
100mA, 500mA, or ≤ 1A input current limits to comply
with USB requirements. Proprietary thermal-regulation
circuitry limits the die temperature to +100°C to prevent
excessive heat on the system PC board. Additional
safety features include an NTC thermistor input (THM)
to protect the battery. A 3.5V to 4.2V SYS output, in
conjunction with the low-R
DSON
battery switch, powers
the system even when the battery is deeply discharged
or not installed. The IC also offers a +3.3V/500µA out-
put (V
L
), a charging status flag (CHG), and an input-
supply detection flag (POK). The MAX8856 operates
from a +4.25V to +5.5V supply and includes undervolt-
age lockout below +3.4V and overvoltage protection
up to +14V.
Applications
Cellular Phones, Smartphones, PDAs
Digital Cameras, MP3 Players
USB Appliances, Charging Cradles and Docks
Features
♦ Small, 3mm x 3mm Thermally Enhanced TDFN
Package (0.8mm max height)
♦ USB-Compliant Suspend Mode (20µA)
♦ Selectable 100mA, 500mA, and Up to 1A Input
Current Limits
♦ USB or AC Adapter Input
♦ +6V to +14V Input Overvoltage Protection
♦ Input UVLO Below +4V Rising (3.5V Falling)
♦ Automatic Current Sharing Between Battery
Charging and System
♦ Die Temperature Regulation (+100°C)
♦ Low Dropout Voltage, 250mV at 0.5A
♦ NTC Thermistor Input
♦ Charge Status and Input-Supply Detection Flags
MAX8856
USB/AC Adapter, Li+ Linear Battery Charger
with Integrated 50m
Ω
Battery Switch in TDFN
________________________________________________________________
Maxim Integrated Products
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