_______________________________________________________________________________________ 7

System Power Management

for Mobile Handset

Note 1: The monitoring voltage is proportional to the charging current with a ratio depending on the programmed fast-charge cur-

rent. For the current equal to the fast-charge current, the monitoring voltage is typically 1.2V.

Note 2: The maximum CHG_IN current is the typical value plus 10% for currents up 700mA and the typical value plus 15% for

higher currents.

Note 3: LED dropout voltage is defined as the LED_ to ground voltage when current into LED_ drops 10% from the value at

VLED_= 0.5V.

ELECTRICAL CHARACTERISTICS (continued)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

LED1, LED2

Current Regulator Dropout Voltage

(Note 3)

25.25mA setting

200

mV

5.05mA setting

150

LED_ Regulation Voltage

350

mV

LED_ Current Accuracy

-3

+3

%

-5

+5

Leakage Current

0.01

1

F

A

1

LX2

nFET Current Limit

710

860

mA

nFET On-Resistance

0.3

0.7

I

LX2 Leakage Current

0.01

1

F

A

1

Operating Frequency

1.8

2

2.2

MHz

Maximum Duty Cycle

92

%

COMP2

Transconductance

20

F

s

Soft-Start Charge Current

60

F

A

Discharge Pulldown

20

kI

PROTECTION

Overvoltage Threshold

28

30

V

Overvoltage Hysteresis

4

V

Open LED Detection

100

120

mV

Shorted LED Detection

- 2.2V

- 0.7V

V