MAX8606
Detailed Description
The MAX8606 charger uses current, voltage, and ther-
mal control loops to charge and protect a single Li+
battery cell. It can start the system even when the bat-
tery is in deep saturation. The MAX8606 provides a
SYS output that supplies the external system with a
minimum 3.5V at 1A.
Two active-low enable inputs (EN1 and EN2) are sup-
plied to set the SYS and charging current limits. During
prequal and fast-charge modes, the CHG output status
flag is pulled low. As the battery voltage approaches
4.2V, the charging current is reduced. When the charg-
ing current drops below 50mA and the battery voltage
equals 4.2V, the CHG output goes high impedance,
signaling a full battery. At any time during charging, if
both EN1 and EN2 are driven high, the charger enters
suspend mode, charging stops, and CHG goes high
impedance.
The MAX8606 contains an internal timer to measure the
prequal, fast-charge, and top-off charge time. If the
battery voltage has not risen above 3V after 30 minutes
or has not completed fast-charge in 8 hours, the charg-
er goes into a fault state where the charging is
USB/AC Adapter, Li+ Linear Battery Charger
with Integrated 50m
Ω
Battery Switch in TDFN
6 _______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1, 2 BAT
Batter y C onnecti on. The IC d el i ver s char g i ng cur r ent and m oni tor s b atter y vol tag e usi ng BAT. C onnect
b oth BAT outp uts tog ether exter nal l y. D ur i ng susp end m od e, BAT i s i nter nal l y connected to S Y S .
3IN
Supply Voltage Input. Connect IN to a 4.25V to 5.5V supply. Charging is suspended if V
IN
exceeds
6V. Bypass IN to GND with a 4.7µF or larger ceramic capacitor.
4VL
+3.3V Output Voltage and Logic Supply. VL is regulated to +3.3V and is capable of sourcing 500µA
to provide power for external circuits. Bypass VL to GND with a 0.1µF or larger ceramic capacitor. VL
is internally pulled to GND during suspend mode.
5 THM
Thermistor Input. Connect a 10kΩ NTC thermistor from THM to GND in close proximity to the battery
to monitor the battery temperature. The IC suspends charging when the temperature is outside the
hot and cold limits. Connect THM to GND to disable the thermistor monitoring function.
6 CHG
Charging Status Output. CHG is an open-drain output that goes low when the battery is charging.
CHG goes high impedance when the charge current drops below 50mA (typ) and the battery voltage
is 4.2V (typ). CHG is high impedance when the IC is in suspend mode.
7 POK P ower - OK M oni tor . P O K i s an op en- d r ai n outp ut that pul l s l ow w hen a val id char g ing sour ce i s d etected at IN .
8 TMR
Timer-Selection Input. Drive TMR high to enable the microprocessor mode where the charge times
are determined by an external device. Drive TMR low to use the internal prequal, fast-charge, and
top-off timers.
9 EN2
Charge-Current Selection Input. Drive EN_ high or low to select the charge current or to put the
MAX8606 into suspend mode (see Table 1).
10 EN1
Charge-Current Selection Input. Drive EN_ high or low to select the charge current or to put the
MAX8606 into suspend mode (see Table 1).
11 GND Ground. Connect directly to exposed paddle under the IC.
12 SETI
Charge-Current Programming Input. Connect a resistor from SETI to GND to set the maximum
charging current. R
SETI
must be between 17.68kΩ and 35.36kΩ.
13, 14 SYS
System Supply Output. SYS delivers up to 1A
RMS
to power an external system. Bypass SYS to GND
with a 4.7µF or larger ceramic capacitor. SYS is connected to BAT through an internal 50mΩ switch
when V
BAT
exceeds 3.5V or when the MAX8606 is in suspend mode.
—EP
Exposed Paddle. Connect to GND under the IC. Connect to a large ground plane to improve power
dissipation.
