MIC23051

4MHz PWM Buck Regulator with

HyperLight Load™ and Voltage Scaling

HyperLight Load is a trademark of Micrel, Inc.

MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.

Protected by US Patent No. 7064531

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

July 2009

M9999-070809-F

General Description

The Micrel MIC23051 is a high efficiency 600mA PWM

synchronous

buck

(step-down)

regulator

featuring

HyperLight Load™, a patented switching scheme that

offers best in class light load efficiency and transient

performance

while

providing

very

small

external

components and low output ripple at all loads.

The MIC23051 has an output voltage scaling feature that

can toggles between two different voltage levels.

The MIC23051 also has a very low typical quiescent

current draw of 20µA and can achieve over 85% efficiency

even at 1mA. The device allows operation with a tiny

inductor ranging from 0.47µH to 2.2µH and uses a small

output capacitor that enables a sub-1mm height solution.

In contrast to traditional light load schemes HyperLight

Load™ architecture does not need to trade off control

speed to obtain low standby currents and in doing so the

device only needs a small output capacitor to absorb the

load transient as the powered device goes from light load

to full load.

At higher loads the MIC23051 provides a constant

switching frequency of greater than 4MHz while providing

peak efficiencies greater than 93%.

from 0.72V to 3.3V eliminating external feedback

2mm MLF

+125

°C.

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

• Input voltage: 2.7V to 5.5V

HyperLight Load™

• 600mA output current

• Fixed output voltage from 0.72V to 3.3V

• Output voltage scaling option

• Ultra fast transient response

• 20µA typical quiescent current

• 4MHz in CCM PWM operation in normal mode

• 0.47µH to 2.2µH inductor

• Low voltage output ripple

–

25mVpp in HyperLight Load mode

–

3mV output voltage ripple in full PWM mode

• >93% efficiency

• ~85% at 1mA

• Micropower shutdown

• –40°C to +125°C junction temperature range

Applications

• Cellular phones

• Digital cameras

• Portable media players

• Wireless LAN cards

• WiFi/WiMax/WiBro modules

• USB Powered Devices

____________________________________________________________________________________________________________

Typical Application

50

60

70

80

90

100

1

10

100

1000

OUTPUT CURRENT (mA)

L = 1µH