SD4054

SD4054 enters shutdown mode, droppi

SD4054 detects an undervolta

3-3

Functional Pin Description

PIN

DESCRIPTION

CHRG

1

Open-Drain Status Output

GND

2

Ground

BAT

3

Charge Current Output

VCC

4

Positive Input Supply Voltage

PROG

5

Charge Current Program, Charge Current Monitor and

Shutdown Pin.

Pin Functions

CHRG (PIN 1):

Open-Drain Charge Status Output. When the battery is charging, the CHRG pin is pulled low by an internal

N-channel MOSFET. When the charge cycle is completed, a weak pull-down of approximately 12µA is connected to

the CHRG pin, indicating a “AC present” condition. When the

ge lockout condition,

CHRG is forced high impedance.

GND (PIN 2): Ground.

BAT (PIN 3):

Charge Current Output. Provides charge current to the battery and regulates the final float voltage to 4.2V. An

internal precision resistor divider from this pin sets the float voltage which is disconnected in shutdown mode.

ng IBAT to less than 2µA.

PROG (PIN 5): Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is

to 1V. In all modes, the voltage on this pin can be used to measure the charge current using the following formula:

The PROG pin can also be used to shutdown the charger. Disconnecting the program resistor from ground allows a

3µA current to pull the PROG pin high. When it reaches the 1.94V shutdown threshold voltage, the charger enters

shutdown mode, charging stops and the input supply current drops to 25µA. This pin is also clamped to

approximately 2.4V. Driving this pin to voltages beyond the clamp voltage will draw currents as high as1.5mA.

(TSOT23-5)

SD4054

SH OU D IN G

SD 4054

SD4054-datasheet V1.0

Sep.-2006

www.shouding.net