MIC3385 8MHz Inductorless Buck Regulator with LDO Standby Mode General Description The Micrel MIC3385 is a high-efficiency inductorless buck regulator that features a LOWQ LDO standby mode that LOWQ draws only 18A of quiescent current. The MIC3385 requires no external inductor enabling an ultra-low noise, Features small size, and high efficiency solution for portable power applications. 2.7 to 5.5V supply voltage In PWM mode, the MIC3385 operates with a constant Light load LOWQ LDO mode frequency 8MHz PWM control. Under light load conditions, 18A quiescent current such as in system sleep or standby modes, the PWM Low noise, 75Vrms switching operation can be disabled to reduce switching 8MHz PWM mode losses. In this light load LOWQ mode, the LDO maintains Output current to 600mA the output voltage and draws only 18A of quiescent >90% efficiency current. The LDO mode of operation saves battery life 100% maximum duty cycle while not introducing spurious noise and high ripple as Adjustable output voltage option down to 1V experienced with pulse skipping or bursting mode Ultra-fast transient response regulators. No external inductor required The MIC3385 operates from 2.7V to 5.5V input and Enables sub 1mm profile solution features internal power MOSFETs that can supply up to Fully integrated MOSFET switches 600mA output current in PWM mode. It can operate with a Micropower shutdown maximum duty cycle of 100% for use in low-dropout Thermal shutdown and current limit protection conditions. Pb-free 14-pin 3x3.5x0.9mm MLF package The MIC3385 is available in the 14-pin 3mm x 3.5mm 40C to +125C junction temperature range MLF package with a junction operating range from 40C to +125C. Applications Data sheets and support documentation can be found on Micrels web site at: www.micrel.com. Slim digital cameras MP3 players Portable power applications Cellular phones PDAs USB peripherals LOWQ is a registered 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 +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC3385 Typical Application 2.5V Efficiency OUT 100 90 V =3.2V IN 80 V =3.6V IN 70 V =4.2V IN 60 50 40 30 20 10 Adjustable Output Buck Regulator with LOWQ Mode 0 0 100 200 300 400 500 600 OUTPUT CURRENT (mA) Ordering Information Part Number Voltage Temperature Range Package Lead Finish MIC3385YHL Adj. 40 to +125C 14-Pin 3mm x 3.5mm MLF Pb-free MIC3385-1.5YHL 1.5V 40 to +125C 14-Pin 3mm x 3.5mm MLF Pb-free Notes: 1. MLF is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. 2. Other voltage options available. Please contact Micrel for details. Revision 3.0 September 22, 2015 2