MIC3385 Datasheet, PDF (1/15 Pages) Micrel Semiconductor – 8MHz Power System Module with LDO Standby Mode

MIC3385
8MHz Power System Module with LDO
Standby Mode
Preliminary Information
General Description
The Micrel MIC3385 is a high efficiency Power System on
a Chip that features a LOWQ™ LDO standby mode that
draws only 18µA of quiescent current. The MIC3385
requires no external inductor enabling an ultra-low noise,
small size, and high efficiency solution for portable power
applications.
In PWM mode, the MIC3385 operates with a constant
frequency 8MHz 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 the output voltage 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 MIC3385 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 MIC3385 is available in the 14-pin 3mm x 3.5mm
MLF^® 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
• 8MHz PWM mode
– Output current to 600mA
– >90% efficiency
– 100% maximum duty cycle
• Adjustable output voltage option down to 1V
• Ultra-fast transient response
• NO external inductor required
• Enables sub 1mm profile solution
• Fully integrated MOSFET switches
• Micropower shutdown
• Thermal shutdown and current limit protection
• Pb-free 14-pin 3mm x 3.5mm MLF^® package
• –40°C to +125°C junction temperature range
Applications
• Cellular phones
• PDAs
• USB peripherals
Typical Application
Adjustable Output Buck Regulator with LOWQ™ Mode
1.8V_OUT Efficiency
100
90 ^VIN=3.2V
80
70
V_IN=3.6V
V_IN=4.2V
60
50
40
30
20
10
00 _{100 200 300 400 500}
OUTPUT CURRENT (mA)
Patent Pending
LOWQ 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
November 2006
1
M9999-111006-A