5

FN6435.0

February 25, 2008

IREF - Charge-current program and monitoring pin. Connect

a resistor between this pin and the GND pin to set the

charge current limit determined by Equation 4:

the actual charge current during the entire charge cycle,

including the trickle, constant-current, and constant-voltage

BATON - Battery disconnect pin. The BATON pin is a logic

input pin to allow the disconnection of the battery from the

system to eliminate the unwanted drainage current from the

battery. There is an internal 1M

Ω pull-down resistor at this

pin. Drive to HIGH to connect the battery to the system.

When this pin is driven to LOW or left floating, the battery is

disconnected from the system.

VOUT - Output connection to the system. This pin provides

a 4.5V regulated voltage for the system when a valid input

power is present. If no valid input is present, and BATON is

driven HI, the VOUT pin is connected to VBAT through an

internal MOSFET. If no valid input is present and BATON is

LOW, the voltage at VOUT pin is zero. A 4.7µF or larger X5R

ceramic capacitor is recommended for decoupling and

stability purposes.

EPAD - Exposed pad. Connect as much copper as possible

to this pad either on the component layer or other layers

through thermal vias to enhance the thermal performance.

I

REF

3886

R

IREF

-----------------

mA

()

=

(EQ. 4)

FIGURE 1. TYPICAL CHARGING CYCLE

Trickle

CC

CV

4.2V

TIME

2.8V

CHG

Charge

Current

Charge

Voltage

CHG

Indication

Timeout

ISL9301