MAX8677A
1.5A Dual-Input USB/AC Adapter Charger
and Smart Power Selector
_______________________________________________________________________________________ 9
Pin Description (continued)
PIN NAME FUNCTION
6 PEN2
USB High/Low Control. PEN2 sets the DC or USB current limit to 100mA (PEN2 low) or 500mA (PEN2 high).
PEN2 controls both DC and USB current limits when PEN1 is low. See Table 2.
7 PSET DC Input Current-Limit Set. Connect a resistor to ground to program the DC current limit to 3000/R
PSET
.
8VL
Logic LDO Output. VL is the output of an LDO that powers the MAX8667A internal circuitry. VL also provides
3.3V at up to 10mA to power external circuitry. Connect a 0.1µF capacitor from VL to GND.
9 GND Ground
10 CT
Charge Timer Program Pin. A capacitor from CT to GND sets the fast-charge (t
FSTCHG
) and prequal (t
PREQUAL
)
fault timers. Connect to GND to disable the timer.
11 ISET
Charge Current Set Input. A resistor (R
ISET
) from ISET to GND programs the maximum charge current up to 1.5A.
The prequal charge current is 10% of the set maximum charge current.
12 THM
Thermistor Input. Connect a negative temperature coefficient (NTC) thermistor that has good thermal contact
with the battery from THM to GND. Connect a resistor equal to the thermistor +25°C resistance from THM to VL.
Charging is suspended when the thermistor is outside the hot and cold limits. Connect THM to GND to disable
the thermistor temperature sensor.
13 USUS
USB Suspend Input. With PEN1 low, driving USUS high turns off both the USB and DC inputs. With PEN1 high,
driving USUS high turns off only the USB input. See Table 2.
14 TSET
Termination Current Set Pin. Connect to GND, leave open, or connect to VL for a 5%, 10%, or 15% (of I
CHGMAX
)
termination current (I
TERM
) threshold.
15, 16 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.
17, 18 BAT
Battery Connection. Connect to a single-cell Li+ battery. The battery charges from SYS when a valid source is
present at DC or USB. BAT powers SYS when neither DC nor USB power is present, or when the SYS load
exceeds the input current limit. Both BAT pins must be connected together externally.
19 CHG
Charger Status Output. Active-low, open-drain output pulls low when the battery is in fast-charge or prequal.
Otherwise, CHG is high impedance.
20, 21 SYS
System Supply Output. SYS is connected to BAT through an internal 40mΩ system load switch when DC or USB
is 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 5.3V. When the system load (I
SYS
) exceeds the
D C or U S B cur r ent l i m i t, S Y S i s r eg ul ated to 68m V b el ow BAT, and b oth the U S B i np ut and the b atter y ser vi ce S Y S .
Bypass SYS to GND with a 10µF X5R or X7R ceramic capacitor. Both SYS pins must be connected together
externally.
22 DOK DC Power-OK Output. Active-low, open-drain output pulls low when a valid input is detected at DC.
23 UOK USB Power-OK Output. Active-low, open-drain output pulls low when a valid input is detected at USB.
24 FLT
Fault Output. Active-low, open-drain output pulls low when the battery timer expires before prequal or
fast-charge complete.
—EP
Exposed Paddle. Connect the exposed paddle to GND. Connecting the exposed paddle does not remove the
requirement for proper ground connections to the appropriate pins.
