MAX8934A Datasheet, PDF (1/31 Pages) Maxim Integrated Products – Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring

19-4995; Rev 1; 3/10
EVAALVUAAILTAIOBNLEKIT
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
General Description
The MAX8934_ dual-input Li+/Li-Poly linear battery char-
gers with Smart Power SelectorK safely charge a single
Li+/Li-Poly cell in accordance with JEITA recommenda-
tions. The MAX8934_ monitors the battery temperature
(TBATT) while charging, and automatically adjusts the
fast-charge current and charge termination voltage as the
battery temperature varies. The MAX8934_ also monitors
the battery temperature while the battery is discharging,
and provides a warning flag (OT) to the system in the
event that the battery is over temperature. Two safety pro-
files are supported (see Figure 6 for details). An ultra-low
IQ, always-on LDO provides an additional 3.3V supply for
system power.
The MAX8934_ operates with either separate inputs
for USB* and AC adapter power, or from a single input
that accepts both. All power switches for charging and
switching the load between battery and external power
are included on-chip. No external MOSFETs are required.
The MAX8934_ features a Smart Power Selector to make
the best use of limited USB or adapter power. Input cur-
rent limit and battery charge current limit are indepen-
dently set. Input power not used by the system charges
the battery. Charge current limit and DC current limit can
be set up to 1.5A and 2A, respectively, while USB input
current can be set to 100mA or 500mA for the MAX8934A/
MAX8934B/MAX8934C/MAX8934E and up to 1.5A (max)
for the MAX8934D. Automatic input selection switches the
system load from battery to external power.
The MAX8934A provides a SYS output voltage of 5.3V,
while the MAX8934B–MAX8934E provides a SYS output
voltage of 4.35V.
Other features include overvoltage protection (OVP),
open-drain charge status and fault outputs, power-OK
monitors, charge timers, and a battery thermistor moni-
tor. Additionally, on-chip thermal limiting reduces the
battery charge-rate to prevent charger overheating.
The MAX8934_ is available in a 28-pin, 4mm x 4mm,
TQFN package.
Applications
PDAs, Palmtop, and Wireless Handhelds
Portable Media, MP3 Players, and PNDs
Digital Still Cameras and Digital Video Cameras
Handheld Game Systems
*Protected by U.S.Patent #6,507,172.
Smart Power Selector is a trademark of Maxim Integrated
Products, Inc.
Features
S Li+ Charger with Smart Power Selector, No
External MOSFETs Needed
S Monitors Battery Temperature and Adjusts Charge
Current and Termination Voltage Automatically
per JEITA Recommendations
S OT Flags System of a Hot Battery During
Discharge
S Ultra-Low IQ, Always-On 3.3V LDO
S Common or Separate USB and Adapter Inputs
S Automatic Adapter/USB/Battery Switchover
S Load Peaks in Excess of Adapter Rating are
Supported by Battery
S Input OVP to 16V (DC) and 9V (USB)
S 40mI SYS-to-BATT Switch
S Thermal Regulation Prevents Overheating
S 4.35V or 5.3V SYS Regulation Voltage
S 1.5A (max) USB Input Current Limit (MAX8934D)
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX8934AETI+
-40NC to +85NC 28 Thin QFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Ordering Information continued and Selector Guide appears
at end of data sheet.
Typical Operating Circuit
AC
ADAPTER
USB
DC Q1
LDO
3.3V ALWAYS-ON
LINEAR
REGULATOR
SYS
CHARGE
CURRENT
LOAD
CURRENT
USB Q2
Q3
CHARGE
AND
SYS LOAD
BATT
SWITCH
GND
MAX8934A−
MAX8934E
SYSTEM
LOAD
BATTERY
________________________________________________________________ Maxim Integrated Products   1
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