MP8709 High Efficiency 4A, 21V, 500kHz Synchronous Step-down Converter The Future of Analog IC Technology DESCRIPTION FEATURES The MP8709 is a high frequency synchronous Wide 4.5V to 21V Operating Input Range rectified step-down switch mode converter with 4A Output Current built in power MOSFETs. It offers a very Low Rds(on) Internal Power MOSFETs compact solution to achieve 4A continuous Low-EMI Switching Speed Technology output current over a wide input supply range High Efficiency Synchronous Mode Operation with excellent load and line regulation. The Fixed 500kHz Switching Frequency MP8709 has synchronous mode operation for Sync from 300kHz to 2MHz External Clock higher efficiency over output current load range. Internal Compensation MP8709 achieves low EMI signature with well Integrated Bootstrap Diode controlled switching edges. OCP Protection (Hiccup Mode) Thermal Shutdown Current mode operation provides fast transient Output Adjustable from 0.8V response and eases loop stabilization. Available in a Thermally Enhanced 8-pin SOIC Full protection features include OCP and package thermal shut down. APPLICATIONS The MP8709 requires a minimum number of Notebook Systems and I/O Power readily available standard external components Networking Systems and is available in a space saving 8-pin SOIC Digital Set Top Boxes package with an exposed pad. Personal Video Recorders Flat Panel Television and Monitors Distributed Power Systems All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Products, Quality Assurance MPS and The Future of Analog IC Technology are Registered Trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION Efficiency V =1.2V OUT 100 V =4.5V IN 90 21 1 4 VIN IN BST 80 70 C1 C4 22uF 0.1uF V =12V IN L1 60 1.8uH V =21V 2,3 IN VOUT 1.2V SW 50 7 VCC MP8709 R1 40 C3 4.99k 0.1uF C2 30 6 47uF FB Rt 20 56k 5 R2 ON/OFF EN/SYNC 10k 10 GND 0 8 0 0.5 1 1.5 2 2.5 3 3.5 4 OUTPUT CURRENT (A) MP8709 Rev. 1.01 www.MonolithicPower.com 1 12/14/2011 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 2011 MPS. All Rights Reserved. EFFICIENCY (%)MP8709 SYNCHRONOUS STEP-DOWN CONVERTER WITH INTERNAL MOSFETS ORDERING INFORMATION Part Number* Package Top Marking Free Air Temperature (T ) A MP8709EN SOIC8E MP8709EN -20 C to +85C * For Tape & Reel, add suffix Z (e.g. MP8709ENZ) For RoHS compliant packaging, add suffix LF (e.g. MP8709ENLFZ) PACKAGE REFERENCE TOP VIEW IN 1 8 GND SW 2 7 VCC SW 3 6 FB BST 4 5 EN/SYNC EXPOSED PAD ON BACKSIDE CONNECT TO GND (4) (1) Thermal Resistance JA JC ABSOLUTE MAXIMUM RATINGS SOIC8E (Exposed Pad) ..........50 ...... 10... C/W Supply Voltage V ....................................... 22V IN V ........................-0.3V (-5V for < 10ns) to 23V SW Notes: V ....................................................... V + 6V 1) Exceeding these ratings may damage the device. BS SW 2) The maximum allowable power dissipation is a function of the All Other Pins..................................-0.3V to +6V maximum junction temperature T(MAX), the junction-to- J Operating Temperature.............. -20C to +85 C ambient thermal resistance , and the ambient temperature JA (2) T . The maximum allowable continuous power dissipation at A Continuous Power Dissipation (T = +25C) A any ambient temperature is calculated by P (MAX)=(T (MAX)- D J ....2.5W T )/ . Exceeding the maximum allowable power dissipation A JA will cause excessive die temperature, and the regulator will go Junction Temperature...............................150C into thermal shutdown. Internal thermal shutdown circuitry Lead Temperature ....................................260C protects the device from permanent damage. 3) The device is not guaranteed to function outside of its Storage Temperature............... -65C to +150 C operating conditions. 4) Measured on JESD51-7, 4-layer PCB. (3) Recommended Operating Conditions Supply Voltage V ...........................4.5V to 21V IN Operating Junct. Temp (T )...... -20 C to +125 C J MP8709 Rev. 1.01 www.MonolithicPower.com 2 12/14/2011 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 2011 MPS. All Rights Reserved.