MAX8903CETI+ Maxim Integrated Products, MAX8903CETI+ Datasheet - Page 23

• Manufacturer Part Number: MAX8903CETI+
• Description: IC DC/DC CHARGER LI+ 2A 28-TQFN
• Manufacturer: Maxim Integrated Products
• Series: Smart Power Selector™r

Specifications of MAX8903CETI+

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 4.1 V ~ 16 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

the current-mode regulator to provide a low-jitter, stable
duty factor operation, the inductor ripple current should
be greater than 200mA in the minimum ripple current
condition. The maximum allowed output inductance
L
and (2) below.
(1)
otherwise,
where T
mum charger output voltage, and V
DC input voltage.
(2)
where L
To obtain a small-sized inductor with acceptable core
loss, while providing stable, jitter-free operation, the
actual output inductance L
an appropriate ripple factor K, and picking an available
inductor in the range of the two values of inductance
yielded by equations (3) and (4) which describe the
maximum ripple current conditions in the minimum on-
time and minimum off-time modes. The recommended
ripple factor ranges from (0.2 ≤ K ≤ 0.4) for (2A ≥ I
1A) designs.
(3)
where T
(4)
where V
the minimum charger output voltage, and T
OUT_MAX
L
T
OUT MIN T
OFF
OFF
OUT _ MAX
OFF
DC(MAX)
L
_
OUT MIN T
is therefore obtained using the equations (1)
=
T
is the minimum off-time obtained from (1).
L
is the minimum off-time, V
100
OFF
OUT MAX
_
_
ns if
is maximum input voltage, V
ON
=
is the maximum allowed inductance.
_
______________________________________________________________________________________
⎛
⎜
⎝
_
⎛
⎜
⎝
1
=
1
−
OFF
−
(
V
V
V
=
V
DC MAX
V
SYS MAX
SYS MAX
2A 1-Cell Li+ DC-DC Chargers for USB
DC MIN
DC MIN
V
=
OUT
SYS MAX
(
(
(
V
(
(
SYS MAX
(
, is obtained by choosing
)
)
)
0 2
)
)
(
K I
−
K I
.
⎞
⎟ ×
⎠
⎞
⎟ ×
⎠
V
×
A
×
)
SYS MIN
DC(MIN)
×
4
DC
DC
4 4 MHz
)
M M Hz
T
SYS(MAX)
×
1
OFF
(
1
T
OFF
≤ 100 ,
)
ON
is minimum
)
×
SYS(MIN)
is the on-
T
ON
ns
is maxi-
DC
is
≥
time at high input voltage, as given by the following
equation:
(5)
otherwise,
The saturation current rating of the inductor must be
greater than the maximum step-down output current
programmed at the IDC pin plus one-half the maximum
ripple current, as given by equation (6).
(6)
where I
inductor, I
programmed at the IDC pin, and IL
greater of the ripple currents obtained from (7) and (8).
(7)
(8)
Table 5 gives recommended inductors for typical
charger applications.
Table 5. Recommended Inductor Examples
DC INPUT VOLTAGE
RANGE, CHARGING
10.8V to 13.2V, 2A
10.8V to 13.2V, 1A
IL
4.5V to 5.5V, 2A
4.5V to 5.5V, 1A
RIPPLE MIN T
CURRENT
SAT
T
IL
ON
and Adapter Power
RIPPLE MIN T
DC
is the saturation current rating of the output
_
=
is the maximum step-down output current
70
I
T
SAT
ON
ns if
_
_
ON
>
=
I
DC
_
⎛
⎜
⎝
1μH inductor, 1072AS-1R0N, TOKO,
DE2818 series, 3.2mm x 3mm x
1.8mm, 25mΩ, 2.6A
1.5μH inductor, MDT2520-CN1R5M,
TOKO, 2.5mm x 2mm x 1.2mm,
95mΩ, 1.25A
1μH inductor, 1072AS-1R0N, TOKO,
DE2818 series, 3.2mm x 3mm x
1.8mm, 25mΩ, 2.6A
2.2μH inductor, MDT2520-CN2R2M,
TOKO, 2.5mm x 2mm x 1.2mm,
105mΩ, 1.20A
V
=
V
V
V
OFF
SYS MIN
DC MAX
SYS MIN
DC MAX
(
+
V
RECOMMENDED INDUCTOR
DC MAX
IL
(
(
(
(
=
RIPPLE MAX
⎝
(
V
SYS MAX
)
)
)
)
×
×
2
)
(
4
4
_
−
L
MHz
L
MHz
V
OUT
1
OUT
1
RIPPLE_MAX
SYS MIN
)
×
⎞
⎟ ≤
⎠
(
T
OFF
70 ,
)
ns
)
×
T
ON
is the
23