MIC4682

Precision Current Limit SOIC-8

SuperSwitcher™ Buck Regulator

SuperSwitcher is a trademark of Micrel, Inc

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

June 2007

M9999-061507

General Description

The MIC4682 is an easy-to-use step-down (buck) switch-

mode voltage regulator. It features a programmable

current limit that allows 10% current limit accuracy over its

full operating temperature range. The precision current

limit makes the MIC4682 ideal for constant-voltage

constant-current applications, such as simple battery

chargers. The precision current limit also gives designers

the ability to set the maximum output current below the

saturation current rating of the inductor. This allows the

use of the smallest possible inductors for a given

application, saving valuable space and cost.

The MIC4682 is a very robust device. Its 4V to 34V input

voltage range allows the MIC4682 to safely be used in

applications where voltage transients may be present.

Additional

protection

features

include

cycle-by-cycle

current limiting and over-temperature shutdown. The

MIC4682 is available in a thermally optimized power

SOIC-8 package that allows it to achieve 2A of continuous

output current.

The MIC4682 requires a minimum number of external

components and can operate using a standard series of

inductors. Compensation is provided internally for fast

transient response and ease of use. The MIC4682 is

available in the 8-pin power SOIC with a –40°C to +125°C

junction temperature range.

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

• Programmable output current limit

–

10% accuracy over temperature

• Wide 4V to 34V operating input voltage range

• Fixed 200kHz PWM operation

• Power SOIC-8 package allows 2A continuous output

current

• All surface mount solution

• Internally compensated

• Less than 1µA typical shutdown-mode current

• Thermal shutdown protection

Applications

• Battery chargers

• White LED drivers

• Constant voltage constant current step-down

converters

• Simple step-down regulator with precise current limit

• USB power supplies

___________________________________________________________________________________________________________

Typical Application

SW

L1

68µH

IN

FB

ISET

SHDN

C2

220µF

10V

R1

3.01k

R3

10M

R4

16.2k

R2

976

5V/1A

MIC4682

C1

10µF

50V

(x2)

+7.5V to +34V

2, 6, 7

1

8

5

4

D1

B240

GND

3

0

1

2

3

4

5

6

0

0.5

1

1.5

2

CURRENT LIMIT (A)

MIC4682 Current Limit

Characteristics

V

Constant Current/Constant Voltage Li-Ion Battery Charger