November 2004

1

MIC2198

MIC2198

Micrel

MIC2198

500kHz 4mm ×

××

×

× 4mm Synchronous Buck Controller

General Description

The MIC2198 is a high-power 500kHz synchronous buck

DC-to-DC controller housed in a small 4mm × 4mm MLF™

12-lead package. The MIC2198 operates from a wide 4.5V to

32V input and can be programmed for output voltages from

0.8V to 6V. The wide input voltage capability makes the

MIC2198 an ideal solution for point-of-load DC-to-DC con-

version in 5V, 12V and higher systems.

The 500kHz switching frequency allows the use of a small

inductor and small output capacitors. The current mode PWM

control along with the external COMP pin allows for ease of

stability compensation and fast transient response across a

wide range of applications.

An all N-Channel synchronous architecture and powerful

output drivers allow up to 20A of output current capability.

For higher efficiency at higher input voltages, refer to the

300kHz MIC2199.

The MIC2198 is available in a 12-pin 4mm × 4mm MLF™

package with a junction temperature range from –40°C to

125°C.

Features

• 4.5V to 32V input range

• 4mm × 4mm MLF™ package

• 500kHz PWM operation

• >90% efficiency

• Output voltage adjustable down to 0.8V

• 20A output current capability

• Drives all N-Channel MOSFETs

• Logic controlled micropower shutdown

• Cycle-by-cycle current limiting

• Adjustable undervoltage lockout

• Frequency foldback overcurrent protection

Applications

• Point-of-load DC-to-DC conversion from 5V, 12V

and higher supplies

• Telecom equipment

• Wireless modems

• Servers

• Base stations

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

Typical Application

IRF7821

IRF7821

1mH

0.01W

3.3V/7A

10kW

6.04kW

1nF

5.5V to 24V

VIN

EN/UVLO

COMP

CSH

LSD

VSW

VDD

BST

HSD

GND

VOUT

FB

2.2nF

2kW

U1 MIC2198BML

SD103BWS

0.1mF

22mF

4.7mF

220mF

5.5V–24V to 3.3V/7A Converter

MLF and

50

55

60

65

70

75

80

85

90

95

100

02468

I

LOAD

(A)

V

V

Efficiency

vs. Load Current