MP28251 20V, 4A Synchronous Step-Down Converter The Future of Analog IC Technology DESCRIPTION FEATURES The MP28251 is a synchronous, rectified, step- Wide 4.75V-to-20V Operating Input Range down, switch-mode converter with internal 4A Output Current power MOSFETs. It offers a very compact Low R Internal Power MOSFETs DS(ON) solution to achieve a 4A continuous output Programmable Switching Frequency current over a wide input supply range with Programmable EN Delay excellent load and line regulation. The Frequency SYNC from 300kHz to 2MHz MP28251 has synchronous mode operation for External Clock higher efficiency over the output current load Low Power Mode Selectable by an External range. Signal Current-mode operation provides a fast External Soft Start transient response and eases loop stabilization. OCP and Thermal Shutdown Full protection features include over-current Available in a 14-pin QFN23 Package protection and thermal shutdown. APPLICATIONS The MP28251 requires a minimal number of DSL Modems readily-available standard external components Cable Modems and is available in a space saving 2mm3mm Set Top Boxes 14-pin QFN package. All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Products, Quality Assurance page. MPS and The Future of Analog IC Technology are registered trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION VIN U1 R5 10 3.3V VOUT IN BS VCC VCC SW R1 ON MP28251 30.1k OFF EN EN C DELAY 47nF RT LPM FB LPM 0 R2 SS 10k FREQ/SYNC FREQ/SYNC GND C SS R FREQ 22nF 30.1k MP28251 Rev. 1.16 www.MonolithicPower.com 1 4/17/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 2013 MPS. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGNS REFER TO MP2384MP28251 20V, 4A SYNCHRONOUS STEP-DOWN CONVERTER ORDERING INFORMATION Part Number Package Top Marking MP28251GD* QFN14 (23mm) ABM * For Tape & Reel, add suffix Z (eg. MP28251GDZ) PACKAGE REFERENCE 2x3 QFN14 (1) (5) ABSOLUTE MAXIMUM RATINGS Thermal Resistance JA JC V ..................................................-0.3V to 22V QFN14 (2x3mm)..................... 70...... 15... C/W IN V ..................................................-0.3V to 23V SW Notes: 1) Exceeding these ratings may damage the device. V ...................................................... V + 6V BST SW 2) Please refer to page 9, Enable Control section, For absolute (2) All Other Pins................................ -0.3V to 6V maximum rating of EN pin. 3) The maximum allowable power dissipation is a function of the Junction Temperature...............................150C maximum junction temperature T (MAX), the junction-to- J Lead Temperature ....................................260C ambient thermal resistance , and the ambient temperature JA (3) T . The maximum allowable continuous power dissipation at A Continuous Power Dissipation (T = +25C) A any ambient temperature is calculated by P (MAX) = (T D J 2x3 QFN14 ................................................ 1.8W (MAX)-T )/ . Exceeding the maximum allowable power A JA dissipation will cause excessive die temperature, and the Junction Temperature 150C regulator will go into thermal shutdown. Internal thermal Operating Temperature.............. -40C to +85C shutdown circuitry protects the device from permanent damage. (4) Recommended Operating Conditions 4) The device is not guaranteed to function outside of its operating conditions. Supply Voltage V .........................4.75V to 20V IN 5) Measured on JESD51-7, 4-layer PCB. Output Voltage V .........................0.8V to 17V OUT Operating Junction Temp. (T ) -40C to +125C J MP28251 Rev. 1.16 www.MonolithicPower.com 2 4/17/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 2013 MPS. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGNS REFER TO MP2384