MAX8900A MAXIM [Maxim Integrated Products], MAX8900A Datasheet - Page 23

• Manufacturer Part Number: MAX8900A
• Manufacturer: MAXIM [Maxim Integrated Products]

The MAX8900_ enters its done state after the charger
has been in the top-off state for t
switching charger is off and no current is delivered to
the battery. Although the charger is off, the SETI and
DNI pins are biased in the done state and the MAX8900_
consumes the associated current from the battery (I
= 1.5V/R
presented to the battery is low (<< 100FA), then a typi-
cal system can remain in the done state for many days.
If left in the done state long enough, the battery voltage
decays below the restart threshold (V
MAX8900_ transitions back into the fast-charge state.
There is no soft-start (di/dt limiting) during the done-to-
fast-charge state transition.
The timer fault state occurs when either the prequalifica-
tion or fast-charge timers expire, or SETI/DNI is shorted
to ground. See the Setting the Fast-Charge Current
(SETI) and Setting the Prequalification Current and Done
Threshold (DNI) sections for more details. In this state
the charger is off. The charger can exit the timer fault
state by either cycling CEN or input power.
The battery hot/cold state occurs when the MAX8900_ is
in any of its charge states (dead battery, prequalification,
fast-charge, top-off) and thermistor temperature is either
less than T1 or greater than T4. In this state, the charger
is off and timers are suspended. The MAX8900_ exits
the temperature suspend state and returns to the state
it came from once the thermistor temperature is greater
than T1 and less than T4. The timer resumes once the
MAX8900_ exits this state.
The V
any of its charge states (dead battery, prequalification,
fast-charge, top-off) and V
state, the charger is off and timers are suspended. The
MAX8900_ exits the V
state it came from when V
The timer resumes once the MAX8900_ exits this state.
As shown in Figure 7, a fault timer prevents the battery
from charging indefinitely. In prequalification and fast-
charge states, the timer is controlled by the capacitance
at CT (C
0.01FF to 1.0FF. Calculate the prequalification time (t
and fast-charge time (t
Rating and JEITA Battery Temperature Monitoring
IN
1.2A Switch-Mode Li+ Chargers with ±22V Input
CT
too high state occurs when the MAX8900_ is in
SETI
). The MAX8900_ supports values of C
+ 1.5V/R
IN
FC
DNI
too high state and returns to the
) as follows (Figure 9):
IN
+ 3FA). If the system load
IN
decreases below V
exceeds V
Battery Hot/Cold State
Charge Timer (CT)
TO
V
. In this state, the
IN
Timer Fault State
RSTRT
Too High State
OVLO
Done State
) and the
. In this
CT
OVLO
from
BAT
PQ
)
.
The top-off time (t
Connect CT to GND to disable the prequalification
and fast-charge timers. With the internal timers of the
MAX8900_ disabled, an external device, such as a FP
can control the charge time through the CEN input.
The MAX8900_ is packaged in a 2.44mm x 2.67mm x
0.64mm, 0.4mm pitch WLP package and withstands
a junction temperature of +150NC. The MAX8900_ is
rated for the extended ambient temperature range from
-40NC to +85NC. Table 1 and Application Note 1891:
Wafer-Level Packaging (WLP) and Its Applications
(www.maxim-ic.com/ucsp) show the thermal charac-
teristics of this package. The MAX8900_ uses several
Figure 9. Charge Times vs. C
1000
C
(nF)
100
150
220
470
68
CT
2000
1800
1600
1400
1200
1000
800
600
400
200
0
141.0
300.0
(min)
0
20.4
30.0
45.0
66.0
t
PQ
t
TO
t
FC
vs. CHARGE TIMER CAPACITOR
PQ
) is fixed at 16s:
200
=
=
180min
t
30min
TO
CHARGE TIMES
1800.0
122.4
180.0
270.0
396.0
846.0
(min)
400
CT
t
FC
=
C
Thermal Management
CT
16s
×
(nF)
×
t
0.1 F
600
FC
0.1 F
C
C
t
CT
PQ
CT
F
F
(hrs)
14.1
30.0
4.5
6.6
2
3
800
1000
t
(s)
16
16
16
16
16
16
TO
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