MIC2198_05 Datasheet, PDF (1/14 Pages) Micrel Semiconductor – 500kHz 4mm × 4mm Synchronous Buck Controller

MIC2198
MIC2198
Micrel, Inc.
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-pin 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
conversion 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
Typical Application
V_IN
5.5V to 24V
22µF
2kΩ
2.2nF
U1 MIC2198BML
VIN
VDD
SD103BWS
4.7µF
EN/UVLO
BST
HSD
VSW
LSD
0.1µF
IRF7821
1µH
IRF7821
COMP
CSH
1nF
VOUT
FB
GND
0.01Ω
V_OUT
3.3V/7A
220µF
10kΩ
6.04kΩ
5.5V–24V to 3.3V/7A Converter
Efficiency
vs. Load Current
100
95
90
85
80
75
70
65
60 ^VIN ^{= 5.5V}
55 ^VOUT ^{= 3.3V}
50
0
2
4
6
8
I_LOAD ^(A)
MLF and MicroLeadFrame are trademarks of Amkor Technology, Inc.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
October 2005
1
MIC2198