MAX8663ETL+T Maxim Integrated Products, MAX8663ETL+T Datasheet - Page 25

• Manufacturer Part Number: MAX8663ETL+T
• Description: IC PMIC LI+ SNGL CELL 40TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX8663ETL+T

• Applications: Handheld/Mobile Devices
• Current - Supply: 900µA
• Voltage - Supply: 4.1 V ~ 8 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

is enabled. It first detects the battery voltage. If the bat-
tery voltage is less than the BAT prequalification thresh-
old (3.0V), the charger enters prequalification mode in
which the battery charges at 10% of the maximum fast-
charge current. This slow charge ensures that the bat-
tery is not damaged by fast-charge current while
deeply discharged. Once the battery voltage rises to
3.0V, the charger transitions to fast-charge mode and
applies the maximum charge current. As charging con-
tinues, the battery voltage rises until it reaches the bat-
tery regulation voltage (4.2V) where charge current
starts tapering down. When charge current decreases
to 7.5% of fast-charge current, the charger enters top-
off mode. Top-off charging continues for 30min, then all
charging stops. If the battery voltage subsequently
drops below the 4.1V recharge threshold, charging
restarts and the timers reset.
ISET adjusts the MAX8662/MAX8663 charging current
to match the capacity of the battery. A resistor from
ISET to ground sets the maximum fast-charge current,
the charge current in prequal, and the charge-current
threshold below which the battery is considered com-
pletely charged. Calculate these thresholds as follows:
Determine the I
acteristics of the battery, and not the capabilities of the
expected AC adapter/USB charging input, the system
load, or thermal limitations of the PCB. The MAX8662/
MAX8663 automatically adjust the charging algorithm
to accommodate these factors.
In addition to setting the charge current, ISET also pro-
vides a means to monitor battery-charge current. The
output voltage of the ISET pin tracks the charge current
delivered to the battery, and can be used to monitor the
charge rate, as shown in Figure 5. A 1.5V output indi-
cates the battery is being charged at the maximum set
fast-charge current; 0V indicates no charging. This volt-
age is also used by the charger control circuitry to set
and monitor the battery current. Avoid adding more
than 10pF capacitance directly to the ISET pin. If filter-
ing of the charge-current monitor is necessary, add a
resistor of 100kΩ or more between ISET and the filter
capacitor to preserve charger stability.
I
CHG-MAX
I
I
PRE-QUAL
TOP-OFF
CHG-MAX
Single-Cell, Li+ Battery-Operated Devices
______________________________________________________________________________________
= 1556 x 1.5V / R
= 7.5% x I
= 10% x I
value by considering the char-
CHG-MAX
CHG-MAX
Charge Current
ISET
Power-Management ICs for
As shown in Figure 3, the MAX8662/MAX8663 feature a
fault timer for safe charging. If prequalification charging
or fast charging does not complete within the time limits,
which are programmed by the timer capacitor at CT, the
charger stops charging and issues a timeout fault.
Charging can be resumed by either toggling CEN or
cycling the DC input voltage.
The MAX8662/MAX8663 support values of C
0.01μF to 1μF:
When the charger exits fast-charge mode, CHG goes
high impedance and top-off mode is entered. Top-off
time is also determined by the capacitance at CT:
In fast-charge mode, the fault timer is suspended when
the charge current is limited, by input or thermal limit-
ing, to less than 20% of I
Figure 5. Monitoring the Battery Charge Current with ISET
Output Voltage
1.5
0
MONITORING THE BATTERY CHARGE CURRENT WITH V
DISCHARGING
t
t
t
TOP OFF
FST CHG
PREQUAL
−
−
BATTERY-CHARGING CURRENT (A)
V
=
=
0
ISET
=
CHG-MAX.
300
300
30
=
min
R
1556
min
min
ISET
×
×
×
x I
0 068
BAT
0 068
0 068
.
C
.
.
C
C
CT
CT
CT
μ
1556 x (1.5V/R
μ
μ
Charge Timer
F
F
F
ISET
CT
ISET
from
)
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