MIC23250 Datasheet, PDF (1/15 Pages) Micrel Semiconductor – 4MHz Dual 400mA Synchronous Buck Regulator with HYPER LIGHT LOAD™

MIC23250
4MHz Dual 400mA Synchronous Buck
Regulator with HYPER LIGHT LOAD™
General Description
Features
The MIC23250 is a high efficiency 4MHz dual 400mA
synchronous buck regulator with Hyper Light Load™. Hyper
Light Load™ provides all the advantages of standard light
load modes, such as low quiescent current and high
efficiency but also allows the use of very small output
capacitors to maintain low output ripple voltage throughout
the entire load range. This benefit is not possible with other
light load mode types as they trade off control speed for low
standby currents. With Hyper Light Load™, the output
capacitor can be reduced by up to a factor of 20 saving cost
and valuable board space. The tiny package (2mm x 2mm
Thin MLF^®) of MIC23250 also saves crucial board space by
using only six external components while regulating two
independent outputs up to 400mA each.
• Input voltage range: 2.7V to 5.5V
• Dual output current 400mA/400mA
• Hyper Light Load™ mode
– 35µA dual quiescent current
– 1µH inductor with a 4.7µF capacitor
• 4MHz in PWM operation
• Ultra fast transient response
• Low voltage output ripple
– 20mVpp in Hyper Light Load™ mode
– 3mV output voltage ripple in full PWM mode
• Up to 94% peak efficiency and 85% efficiency at 1mA
• Fully integrated MOSFET switches
• Micropower shutdown
The device is designed for use with a 1µH inductor and a
4.7µF output capacitor that enables a sub-1mm height.
The MIC23250 has a very low quiescent current of 35µA
and can achieve over 85% efficiency at 1mA. At higher
loads the MIC23250 provides a constant switching
frequency around 4MHz while providing peak efficiencies up
to 94%.
• Thermal shutdown and current limit protection
• Fixed output:10-pin 2mm x 2mm Thin MLF^®
• Adjustable output:12-pin 2.5mm x 2.5mm Thin MLF^®
(Available in Q2/Q3 2008)
• –40°C to +125°C junction temperature range
Applications
The MIC23250 fixed output voltage option is available in a
10-pin 2mm x 2mm Thin MLF^® with a junction operating
range from –40°C to +125°C. The adjustable output voltage
option will soon be available in Q2/Q3 2008.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
• Mobile handsets
• Portable media players
• Portable navigation devices (GPS)
• WiFi/WiMax/WiBro modules
• Digital cameras
• Wireless LAN cards
• USB Powered Devices
___________________________________________________________________________________________________________
Typical Application
Efficiency VOUT = 1.8V
100
90 ^{VIN = 2.7V VIN = 3.0V}
80
70 VIN = 4.2V
VIN = 3.6V
60
50
40
30
20
10
L = 1µH
COUT = 4.7µF
01
10
100
1000
LOAD (mA)
Hyper Light Load is a trademark of Micrel, Inc.
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
December 2007
M9999-121707-A