LM3658SDX/NOPB National Semiconductor, LM3658SDX/NOPB Datasheet - Page 8

• Manufacturer Part Number: LM3658SDX/NOPB
• Description: IC USB/AC LI-ION CHARGER 10-LLP
• Manufacturer: National Semiconductor
• Type: Battery Chargerr

Specifications of LM3658SDX/NOPB

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Voltage - Supply: 4.35 V ~ 6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-WFDFN Exposed Pad
• Output Current: 25mA
• Output Voltage: 4.2V
• Operating Supply Voltage (min): 4.35V
• Operating Supply Voltage (max): 6V
• Operating Temp Range: -40C to 85C
• Package Type: LLP EP
• Mounting: Surface Mount
• Pin Count: 10
• Operating Temperature Classification: Industrial
• For Use With: LM3658SDEV - BOARD EVALUATION LM3658SD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM3658SDX

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LM3658 Operation Description
POWER-DOWN MODE
The LM3658 will power down automatically when the voltage
on the USBpwr or CHG_IN pin drops below the battery volt-
age with an amount that is equal to V
V
FETs as well as the open-drain pull-down transistors on the
status pins STAT1 and STAT2. The only current consumed
by the LM3658 is an ultra-low quiescent current of 1 µA typi-
cal.
POWER-ON RESET
As soon as the voltage of one of the power sources rises
above V
charging will not be initiated unless the supply voltage source
exceeds the V
AUTOMATIC POWER SOURCE DETECTION
When the voltage of one of the power sources exceeds the
V
valid charge supply. When both supply voltages are valid and
present, CHG_IN will automatically be selected over USBpwr.
The USBpwr will be the designated power source only if no
CHG_IN is present or when the voltage on the CHG_IN pin is
less than the battery voltage.
THERMAL POWER FET REGULATION
The internal power FETs are thermally regulated to the junc-
tion temperature of 120ºC to guarantee optimal charging of
the battery. At all times is the charge current limited by the
I
the 100ºC junction temperature of the LM3658. The charge
current is therefore a function of the charge current settings,
the thermal conductivity of the package and the ambient tem-
perature as described in the following equation:
Where T
resistance of the package. Thermal regulation guarantees
maximum charge current and superior charge rate without
exceeding the power dissipation limits of the LM3658.
PRE-QUALIFICATION MODE
During pre-qualification, STAT1 is on and STAT2 is off, and
the charger supplies a constant current of 50 mA to the bat-
tery. When the battery voltage reaches V
er transitions from pre-qualification to full-rate charging. The
pre-qualification mode aborts when the battery doesn’t reach
V
event, charging stops and STAT1 and STAT2 will both be on,
indicating a bad battery condition.
CHG_IN FULL-RATE CHARGING MODE
The full-rate charge cycle is initiated following the successful
completion of the pre-qualification mode. Timer T
count when the charger enters full-rate charging, with STAT1
on and STAT2 off. When charging with an AC wall adapter,
the full-rate charge current is proportional to the value of the
resistor that is connected to the I
following equation:
SET
OK_CHG
POR
FULL_RATE
resistor setting, the USB 100 mA/500 mA selection, or
threshold, the LM3658 detects which power source is a
BATT
). Power-Down mode shuts off the internal power
A
is the ambient temperature and θ
within the time allowed in T
+ V
POR
OK_CHG
.
, the charger will wake up. However,
SET
pin as described in the
OK_CHG
PREQUAL
FULL_RATE
JA
(V
is the thermal
timer. In this
BATT
20128205
CHG
, the charg-
starts to
> V
CC
-
8
It is recommended to charge Li-Ion batteries at 1C rate, where
“C” is the capacity of the battery. As an example, it is recom-
mended to charge a 750 mAh battery at 750 mA, or 1C.
Charging at a higher rate can cause damage to the battery.
USBpwr FULL-RATE CHARGING MODE
The full-rate charge cycle is initiated following the successful
completion of the pre-qualification mode. Timer T
count when the charger enters full-rate charging, with STAT1
on and STAT2 off. If the USB bus provides the charger supply,
then the default full-rate charge current is 100 mA max unless
the USB_sel pin is pulled high, which sets the charge current
to 500 mA max.
CONSTANT-VOLTAGE CHARGING MODE AND END-OF-
CHARGE (EOC) DETECTION
The battery voltage increases rapidly as a result of full-rate
charging and will reach the 4.2V termination voltage, trigger-
ing the constant-voltage charge cycle. Timer T
to count in this cycle. STAT1 is on and STAT2 is off. The
charge current gradually decreases during constant-voltage
charging until it reaches the End-Of-Charge (EOC), which is
equal to 10% of the full-rate current set either by the resistor
connected to the I
times out before EOC is reached, charging stops and STAT1
and STAT2 will both be on, indicating a bad battery condition.
TOP-OFF CHARGING MODE
Once EOC has been reached, a top-off cycle continues to
charge the battery. Timed top-off cycle provides optimal bat-
tery capacity following a complete charge cycle. During this
cycle, charging terminates when I
rate charge current or when T
occurs first. STAT1 will turn off and STAT2 will turn on once
the top-off cycle completes successfully, indicating that
charging is done.
MAINTENANCE MODE
Maintenance mode begins immediately after the charger suc-
cessfully finishes the top-off cycle. In the maintenance mode,
the battery voltage is being monitored by the LM3658 contin-
uously. If the battery voltage drops 200 mV below V
new full-rate charge cycle starts to replenish the battery. As
this new full-rate charge cycle begins, STAT1 will turn on and
STAT2 will turn off, and all the timers will reset. Refer to the
LM3658 Flowchart.
CHARGE STATUS OUTPUTS
The LM3658 provides two open-drain outputs STAT1 and
STAT2 that can be connected to external LEDs or to General
Purpose I/O’s (GPIO) of a peripheral IC. All charge status of
the LM3658 is illustrated in Table 1. “ON” means that STATx
pin is pulled low as its pull-down transistor is turned on, rep-
resenting a logic 0.
SET
pin or the USB_sel pin. If Timer T
TOPOFF
CHG
reaches 2.5% of the full-
times out, whichever
CHG
CHG
continues
starts to
TERM
CHG
, a