MIC2206 Datasheet, PDF (1/12 Pages) Micrel Semiconductor – 2MHz PWM Synchronous Buck Regulator with LOWQ Mode and Voltage Scaling

MIC2206
2MHz PWM Synchronous Buck
Regulator with LOWQ Mode and Voltage
Scaling
General Description
The Micrel MIC2206 is a high efficiency 2MHz PWM
synchronous buck (step-down) regulator that
features a LOWQ™ LDO standby mode that draws
only 18µA of quiescent current. The MIC2206
allows an ultra-low noise, small size, and high
efficiency solution for portable power applications.
In PWM mode, the MIC2206 operates with a
constant frequency 2MHz PWM control. Under light
load conditions, such as in system sleep or standby
modes, the PWM switching operation can be
disabled to reduce switching losses. In this light
load LOWQ™ mode, the LDO maintains an output
voltage of 1V and draws only 18µA of quiescent
current. The LDO mode of operation saves battery
life while not introducing spurious noise and high
ripple as experienced with pulse skipping or bursting
mode regulators.
The MIC2206 operates from 2.7V to 5.5V input and
features internal power MOSFETs that can supply
up to 600mA output current in PWM mode. It can
operate with a maximum duty cycle of 100% for use
in low-dropout conditions.
The MIC2206 is available in the 3mm x 3mm MLF-
10L package 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.
Features
• 2.7 to 5.5V supply voltage
• Light load LOWQ™ LDO mode
18µA quiescent current
Low noise, 75µVrms
• 2MHz PWM mode
Output current to 600mA
>95% efficiency
100% maximum duty cycle
• Output Voltage Scaling (1V output in LOWQ
Mode)
• Ultra-fast transient response
• Stable with 1µF ceramic output capacitor
• Fully integrated MOSFET switches
• Micropower shutdown
• Thermal shutdown and current limit protection
• Pb-free 3mm x 3mm MLF-10L package
• –40°C to +125°C junction temperature range
Applications
• Cellular phones
• PDAs
• USB peripherals
____________________________________________________________________________________________________
Typical Application
V_IN
Li Ion
Battery
C_IN
4.7µF
0.1µF
MIC2206
VIN
AVIN
LDO
SW
EN
FB
LOWQ PGND
BIAS AGND
2.2µH
100pF
V_OUT
1.8V/600mA
C_OUT
2.2µF
Ceramic
Fixed Output Buck Regulator with LOWQ™ Mode
LOWQ is a trademark of Micrel, Inc
Micrel, Inc. • 2180 Fortune Drive • San Jose, Ca 95131 • USA • tel [phone] • fax [phone] • http://www.micrel.com
April 2005
M9999-041905
[e-mail]