MIC4744
4 MHz Dual 2A Integrated Switch
Buck Regulator
General Description
The Micrel MIC4744 is a high efficiency dual PWM buck
(step-down) regulator that provides dual 2A current output.
The MIC4744 operates at 4MHz. A proprietary internal
compensation technique allows a closed loop bandwidth of
over 200kHz.
The low on-resistance internal P-Channel MOSFET of the
MIC4744 allows efficiencies over 90%, reduces external
components count and eliminates the need for an
expensive current sense resistor.
The MIC4744 operates from 2.9V to 5.5V input and the
output can be adjusted down to 0.6V. The device can
operate with a maximum duty cycle of 100% for use in low-
dropout conditions.
The MIC4744 is available in the exposed pad 16-pin
3mm x 3mm MLF
®
and ETSSOP-16 packages with
junction operating temperature ranging from –40°C to
+125°C.
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
Features
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2.9 to 5.5V supply voltage
4MHz PWM mode
2A Dual output
Greater than 90% efficiency
100% maximum duty cycle
Output voltage adjustable down to 0.6V
Ultra-fast transient response
Ultra-small external components
Stable with a 0.47µH inductor and a 10µF output
capacitor
Fully integrated 2A MOSFET switches
Micro-power shutdown
Thermal shutdown and current limit protection
Available in 3mm x 3mm 16-pin MLF
®
and 16-pin
TSSOP packages
–40°C to +125°C junction temperature range
Broadband: xDSL modems
Automotive satellite radios
HD STB, DVD/TV recorder
Computer peripherals: printers and graphic cards
FPGA/ASIC
General point of load
Applications
Typical Application
5.0Vin 3.3Vout Efficiency
100
98
96
EFFICIENCY (%)
94
92
90
88
86
84
82
80
0.0
0.4
0.8
1.2
1.6
2.0
OUTPUT CURRENT (A)
2A 4MHz Dual Buck Regulator
MLF and
MicroLeadFrame
are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
March 2009
1
M9999-030209-C
MICREL [ MICREL SEMICONDUCTOR ]
