MIC23051 Datasheet, PDF (1/13 Pages) Micrel Semiconductor – 4MHz PWM Buck Regulator 4MHz PWM Buck Regulator and Voltage Scaling

MIC23051
4MHz PWM Buck Regulator
with HYPER LIGHT LOAD™
and Voltage Scaling
General Description
Features
The Micrel MIC23051 is a high efficiency 500mA PWM
synchronous buck (step-down) regulator featuring Hyper
Light Load™, a patented switching scheme that offers best
in class light load efficiency and transient performance
while providing very small external components and low
output ripple at all loads.
The MIC23051 has an output voltage scaling feature that
can toggles between two different voltage levels.
The MIC23051 also has a very low typical quiescent
current draw of 20µA and can achieve over 85% efficiency
even at 1mA. The device allows operation with a tiny
inductor ranging from 0.47µH to 2.2µH and uses a small
output capacitor that enables a sub-1mm height.
In contrast to traditional light load schemes Hyper Light
Load™ architecture does not need to trade off control
speed to obtain low standby currents and in doing so the
device only needs a small output capacitor to absorb the
load transient as the powered device goes from light load
to full load.
At higher loads the MIC23051 provides a constant
switching frequency of greater than 4MHz while providing
peak efficiencies greater than 93%.
• Input voltage range: 2.7V to 5.5V
• Fixed output voltage options from 0.72V to 2.5V
• Output voltage scaling option
• Output current to 500mA
• Ultra fast transient response
• 20µA typical quiescent current
• 4MHz in CCM PWM operation in normal mode
• Hyper light load mode
• 0.47µH to 2.2µH inductor
• Low voltage output ripple
– 25mVpp in hyper light load mode
– 3mV output voltage ripple in full PWM mode
• >93% efficiency
• ~85% at 1mA
• Fully integrated MOSFET switches
• Micropower shutdown
• Thermal shutdown and current limit protection
• 8-pin 2mm x 2mm MLF^®
• –40°C to +125°C junction temperature range
Applications
The MIC23051 comes in fixed output voltage options from
0.72V to 2.5V eliminating external feedback components.
The MIC23051 is available in an 8-pin 2mm x 2mm MLF^®
with a junction operating range from –40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
• Cellular phones
• Digital cameras
• Portable media players
• Wireless LAN cards
• WiFi/WiMax/WiBro modules
• USB Powered Devices
___________________________________________________________________________________________________________
Typical Application
Efficiency V_OUT = 1.8V
100
VIN = 2.7V
80
V_IN = 3.3V
V_IN = 3.6V
60
40
20
V_OUT = 1.8V
L = 1µH
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.
Protected by US Patent No. 7064531
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
October 2007
M9999-101207-C