Datasheet

13
Maxim Integrated
Dual-Input Linear Charger, Smart Power Selector
with Advanced Battery Temperature Monitoring
MAX8934G
Pin Description (continued)
PIN NAME FUNCTION
17 LDO
Always-On Linear Regulator Output. LDO is the output of an internal always-on 3.3V LDO that provides
power to external circuitry. The LDO output provides up to 30mA of current for indicator LEDs or other
loads. LDO remains active even when only a battery is present, so that the thermistor monitor circuitry
can be activated when the battery is being discharged, and other circuitry can remain powered.
Connect a 1FF ceramic capacitor from LDO to GND.
18, 19 USB
USB Power Input. USB is capable of delivering up to 0.5A to SYS. The USB current limit is set with
PEN2 and USUS. See Table 2. Both USB pins must be connected together externally. Connect a 4.7FF
ceramic capacitor from USB to GND.
20, 21 BATT
Battery Connection. Connect the positive terminal of a single-cell Li+ battery to BATT. The battery
charges from SYS when a valid source is present at DC or USB. BATT powers SYS when neither DC nor
USB power is present, or when the SYS load exceeds the input current limit. Both BATT pins must be
connected together externally.
22
CHG
Charger Status Output. The CHG active-low, open-drain output pulls low when the battery is in fast
charge or prequal. Otherwise, CHG is high impedance.
23, 24 SYS
System Supply Output. SYS is connected to BATT through an internal 40mI system load switch when
DC or USB are invalid, or when the SYS load is greater than the input current limit.
When a valid voltage is present at DC or USB, SYS is limited to or 4.35V. When the system load (I
SYS
)
exceeds the DC or USB current limit, SYS is regulated to 75mV below V
BATT
and both the input and the
battery service the SYS load. Bypass SYS to GND with a 10FF ceramic capacitor. Both SYS pins must
be connected together externally.
25
OT
Battery Overtemperature Flag. The OT active-low, open-drain output pulls low when THMEN is high and
the battery temperature is R +75NC.
26
DOK
DC Power-OK Output. The DOK active-low, open-drain output pulls low when a valid input is detected
at DC.
27
UOK
USB Power-OK Output. The UOK active-low, open-drain output pulls low when a valid input is detected
at USB.
28
FLT
Fault Output. The FLT active-low, open-drain output pulls low when the battery timer expires before
prequal or fast charge complete.
— EP
Exposed Pad. Connect the exposed pad to GND. Connecting the exposed pad does not remove the
requirement for proper ground connections to the appropriate pins.