LN2053

Rev.1.1 —Aug. 20, 2015

3

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■ Pin Function



TS (Pin 1): The TS pin to the battery of the NTC sensor output. If the TS pin voltage is less than the input voltage of 30%

or greater than 60% of the input voltage means the battery temperature is too low or too high, then the charge will be

suspended. If the TS input voltage between 30% and 60%, then the battery fault condition will be cleared, the charge will

continue. Battery temperature sensing feet, when not use , please contact GND.



ISET (Pin 2): Charge current programming, charge current monitoring and close pin. Charge current is controlled by a

resistor of precision of 1%to the ground. In the constant charge current state, this port provides 1V voltage. In all conditions,

this port charge current can be calculated using the following formula:

IBAT = (VISET/RISET) ×1250

ISET port can also be used to turn off the charger. Resistance to side with the separation of programming can pull the 3µA

current source to increase ISET port voltage. When the suspension reached the limit voltage 1.21V, the device enters stop

state, after charging the input current drop to 25µA. This port pinch-off voltage is about 2.4V. If supply this port voltage

more than pinch-off voltage, the current will be 1.5 mA. Through combinating ISET pin to the ground, the charger will back

to normal.



GND (Pin 3): Ground terminal



VIN (Pin 4): Supply positive input voltage. Power supply for the charger. VCC can be 4.25V to 6.5V and must have at least

1F bypass capacitor. If the BAT pin voltage of VCC down to within 30 mV, LN2052 into the suspension state, and make

BAT Current less than 2A.



BAT (Pin 5): Make the battery's positive terminal connected to this pin. When the power supply voltage lower than the

threshold latch voltage or sleep mode voltage, BAT pin current is less than 2

μA. BAT pin provide the battery charge current

and constant voltage charging voltage.



DONE (Pin 6): When charging end, DONE pin is pulled low by internal switch represents that charge has ended;

otherwise DONE pin is high impedance state.



CHRG (Pin 7): When the charger to the battery charging, CHRG pin is pulled low by the internal switch,represents

charging being; otherwise CHRG pin is in high impedance state.



FB (Pin 8): This pin foot iron phosphate power battery access. When FB and BAT shorted, the output is 3.65V. If connect a

resistor between the FB pin and BAT pin, constant charging voltage can be adjusted.