LP3923

SNVS567B – APRIL 2010 – REVISED MAY 2013

www.ti.com

Buck Converter Electrical Characteristics (continued)

Unless otherwise noted, VIN = VINB = 3.6V, GND = 0V, CVINB = 10 µF. Typical values and limits appearing in normal type

apply for TJ = 25°C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TA = TJ

=

−40°C to +125°C.

(1)(2)

Limit

Symbol

Parameter

Conditions

Typ

Units

Min

Max

VOUT,PFM

Output Voltage regulation

See(3)

in PFM mode relative to

1.5

%

regulation in PWM mode

Line Regulation

3.0V

≤ VIN ≤ 5.5V, IOUT = 10

0.14

%/V

mA

VOUT

Load Regulation

100 mA

≤ IOUT ≤ 300 mA

0.0013

%/mA

ILIM_PWM

Switch Peak Current Limit

PWM Mode

1150

800

1500

mA

RDSON(P)

P Channel FET on

VIN = 3.6V

310

m

Ω

Resistance

IDS = 100 mA

RDSON(N)

N Channel FET on

160

m

Ω

Resistance

fOSC

Internal Oscillator

PWM Mode

2

1.9

2.1

MHz

Frequency

Efficiency

IOUT = 5 mA, PFM Mode

88

VOUT = 1.8V

(3)

%

IOUT = 300 mA, PWM Mode

90

VOUT = 1.8V

(3)

TSTUP

Start Up Time

IOUT = 0

(3), V

OUT = 1.8V

140

µs

Charger Electrical Characteristics

Unless otherwise noted, VCHG_IN = 5V, VIN= BATT = 3.6V, CCHG_IN = 1 μF, VBATT = 30 µF. Typical values and limits appearing

in normal type apply for TJ = 25°C. Limits appearing in boldface type apply over the entire junction temperature range for

operation, TA = TJ = −25°C to +85°C.

(1) (2)

Symbol

Parameter

Conditions

Typical

Limit

Units

Min

Max

VCHG_IN

AC wall adapter input

4.5

6.8

V

voltage operating range

CHG_IN OK trip-point.

VCHG_IN - VBATT (Rising)

150

VOK_CHG

mV

VCHG_IN - VBATT (Falling)

40

Battery charging

VTERM = 4.2V, ICHG = 50 mA

-0.35

+0.35

VTERM

termination voltage

VTERM is measured at 10% of the programmed

%

-1

+1

tolerance

ICHG current

ICHG

CHG_IN programmable

6.8V

≥ VCHG_IN ≥ 4.5V

full-rate charging current

VBATT < VCHG_IN − VOK_CHG

50

1200

mA

VFULL_RATE < VBATT < VTERM

(3)

Full rate charging current

ICHG = 400 mA

−10

+10

%

tolerance

IPREEQUAL

Pre-charging current

2.2V < VBATT < VFULL_RATE

50

30

70

mA

VFULL_RATE

Full-rate qualification

VBATT rising, transition from pre-charging to full-

2.8

2.7

2.9

threshold

rate charging

V

VBATT rising, transition from pre-charging to full-

3.0

2.9

3.1

rate charging (LP3923-VC)

(1)

All limits are specified. All electrical characteristics having room-temperature limits are tested during production with TJ = 25°C. All hot

and cold limits are ensured by correlating the electrical characteristics to process and temperature variations and applying statistical

process control.

(2)

Junction-to-ambient thermal resistance is highly application and board-layout dependent. In applications where high maximum power

dissipation exists, special care must be paid to thermal dissipation issues in board design.

(3)

Full charging current is ensured for CHG_IN = 4.5 to 6.8V, but particularly at higher input voltages. Increased power dissipation may

cause the thermal regulation to limit the current to a safe level, resulting in longer charging time.

12

Submit Documentation Feedback

Copyright © 2010–2013, Texas Instruments Incorporated

Product Folder Links: LP3923