May 2004

1

M9999-052104

MIC2202

Micrel

Typical Application

MIC2202

High Efficiency 2MHz Synchronous Buck

Converter 1

General Description

The Micrel MIC2202 is a high efficiency 2MHz PWM synchro-

nous buck regulator. The fast 2MHz operation along with a

proprietary compensation scheme allows the smallest pos-

sible external components. The MIC2202 can operate with

a 1

µF ceramic output capacitor and a small, low DC-resis-

tance, 2.2

µH inductor, reducing system size and cost while

allowing a high level of efficiency.

The MIC2202 operates from 2.3V to 5.5V input and features

internal power MOSFETs that can supply over 600mA of

output current with output voltages down to 0.5V. The

MIC2202 implements a constant 2MHz pulse- width-modu-

lation (PWM) control scheme which reduces noise in sensi-

tive RF, audio, and communications applications. Addition-

ally, the MIC2202 can be synchronized to an external clock,

or multiple MIC2202s can easily be daisy-chained with the

SYNCLOCK feature.

The MIC2202 has a high bandwidth loop (up to 500kHz)

which allows ultra fast transient response times. This is very

useful when powering applications that require fast dynamic

response such as CPU cores and RF circuitry in high

performance cellular phones and PDAs.

The MIC2202 is available in 10-pin MSOP and 3mm

× 3mm

MLF™-10L package options with an operating junction

temperature range from –40

°C to +125°C .

Features

• Input voltage range: 2.3V to 5.5V

• Output down to 0.5V/600mA

• 2MHz PWM operation

• Stable with 1

µF ceramic output capcitor.

• Ultra-fast transient response (up to 500kHz GBW)

• Internal compensation

• All ceramic capacitors

• >95% efficiency

• Fully integrated MOSFET switches

• Easily synchronized to external clock

• SYNCLOCK feature to daisy chain multiple 2202s

• Requires only 4 external components

• 1% line and load regulation

• Logic controlled micropower shutdown

• Thermal shutdown and current limit protection

• 10-pin MSOP and 3mm

×3mm MLF™-10L package

options

• –40

°C to +125°C junction temperature range

Applications

• Cellular phones

• PDAs

• 802.11 WLAN power supplies

• FPGA/ASIC power supplies

• Dynamically adjustable power supply for CDMA/W-

CDMA RF power amps

• DSL modems

• Tape drives

10nF

2.2

µH

3.3V

600mA

2.3V to 5.5V

1

µF

10k

1.78k

EN

6

5

1

SYNC_IN

SYNC_OUT

10

9

8

7

2

3

4

Adjustable Output Synchronous Buck Converter

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

60

65

70

75

80

85

90

95

100

0

0.1

0.2

0.3

0.4

0.5

0.6

OUTPUT CURRENT (A)

Efficiency 3.3V

OUT

5V

IN

4.2V

IN

L = 2.2

µH

C