April 2005

1

MIC4690

MIC4690

Micrel

MIC4690

500kHz 1A SuperSwitcher™ Buck Regulator

General Description

The MIC4690 SuperSwitcher™ is an easy-to-use, 500kHz

step-down PWM voltage regulator. The MIC4690 achieves

over 1A of continuous output current over a wide input voltage

range in an 8-lead SO (small outline) package.

The high switching frequency of the MIC4690 allows the

smallest surface-mount inductors and capacitors to be used.

Internal compensation ensures fast transient response and a

minimum amount of external components.

The MIC4690 features a power SO-8 package with a special

lead frame that allows over 1A of continuous current. The

MIC4690, housed in an SO-8, can replace larger TO-220 and

TO-263 packages in many applications.

The MIC4690 allows for a high degree of safety. It has a wide

input voltage range of 4V to 34V, allowing for it to be used in

applications where input voltage transients may be present.

Built-in safety features include over-current protection, fre-

quency foldback protection, and thermal shutdown.

The MIC4690 is available in an 8-lead SO package with a

junction temperature range of –40°C to +125°C.

Typical Application

SW

L1

10µH

VIN

FB

GND

SHDN

C2

100µF

4V

R1

3.01k

R2

2.94k

2.5V/1A

MIC4690BM

C1

22µF

10V

5V

SHUTDOWN

ENABLE

Power

SOP-8

5Ð8

4

3

2

1

D1

2A

20V

2.5V Adjustable Converter

SW

L1

18µH

VIN

FB

GND

SHDN

C2

220µF

4V

R1

3.01k

R2

6.49k

1.8V/1A

MIC4690BM

C1

22µF

10V

4V to 30V

(34V Transient)

SHUTDOWN

ENABLE

Power

SOP-8

5Ð8

4

3

2

1

D1

2A

20V

1.8V Adjustable Converter

Features

• SO-8 package with over 1A output current

• Fixed 500kHz operation

• Wide 4V to 34Vinput voltage range

• Output voltage adjustable to 1.23V

• All surface mount solution

• Internally compensated with fast transient response

• Up to 85% efficiency

• Overcurrent protection

• Frequency foldback short-circuit protection

• Thermal shutdown

Applications

• Simple 1A step-down (buck) regulator

• Replacement of TO-220 and TO-263 designs

• 12V to 5V/3.3V/2.5V/1.8V/1.5V conversion

• 5V to 2.5V/1.8V/1.5V conversion

• On-card switching regulators

• Hard disk drives

• Cable modems

• Positive-to-negative converters

• Simple battery chargers

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

SuperSwitcher is a trademark of Micrel, Inc.