MAX15041 19-4815 Rev 3 3/11 Low-Cost, 3A, 4.5V to 28V Input, 350kHz, PWM Step-Down DC-DC Regulator with Internal Switches General Description Features Up to 3A of Continuous Output Current The MAX15041 low-cost, synchronous DC-DC convert- er with internal switches delivers an output current up to 1% Output Accuracy Over Temperature 3A. The MAX15041 operates from an input voltage of 4.5V to 28V Input Voltage Range 4.5V to 28V and provides an adjustable output voltage Adjustable Output Voltage Range from 0.606V to from 0.6V to 90% of V , set with two external resistors. IN 0.9 x V IN The MAX15041 is ideal for distributed power systems, Internal 170m R High-Side and 105m DS-ON preregulation, set-top boxes, television, and other con- R Low-Side Power Switches DS-ON sumer applications. Fixed 350kHz Switching Frequency The MAX15041 features a peak-current-mode PWM con- Up to 93% Efficiency troller with internally fixed 350kHz switching frequency and a 90% maximum duty cycle. The current-mode con- Cycle-By-Cycle Overcurrent Protection trol architecture simplifies compensation design, and Programmable Soft-Start ensures a cycle-by-cycle current limit and fast response Stable with Low-ESR Ceramic Output Capacitors to line and load transients. A high-gain transconductance Safe Startup into Prebiased Output error amplifier allows flexibility in setting the external com- pensation by using a type II compensation scheme, Enable Input and Power-Good Output thereby allowing the use of all ceramic capacitors. Fully Protected Against Overcurrent and Overtemperature This synchronous buck regulator features internal MOSFETs that provide better efficiency than asynchro- V LDO Undervoltage Lockout DD nous solutions, while simplifying the design relative to Space-Saving, Thermally Enhanced, 3mm x 3mm discrete controller solutions. In addition to simplifying Package the design, the integrated MOSFETs minimize EMI, reduce board space, and provide higher reliability by Ordering Information minimizing the number of external components. The MAX15041 also features thermal shutdown and PIN- TOP PART TEMP RANGE overcurrent protection (high-side sourcing and low-side PACKAGE MARK sinking), and an internal 5V LDO with undervoltage MAX15041ETE+ -40C to +85C 16 TQFN-EP* AGV lockout. In addition, this device ensures safe startup +Denotes a lead(Pb)-free/RoHS-compliant package. when powering into a prebiased output. *EP = Exposed pad. Other features include an externally adjustable soft-start that gradually ramps up the output voltage and reduces Typical Operating Circuit inrush current. Independent enable control and power- good signals allow for flexible power sequencing. INPUT The MAX15041 is available in a space-saving, high- 12V power, 3mm x 3mm, 16-pin TQFN-EP package and is fully specified from -40C to +85C. IN BST OUTPUT Applications EN 1.8V AT 3A MAX15041 LX Distributed Power Systems V DD Wall Adapters PGND Preregulators Set-Top Boxes PGOOD FB Televisions PGOOD SS COMP xDSL Modems SGND Consumer Products Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLELow-Cost, 3A, 4.5V to 28V Input, 350kHz, PWM Step-Down DC-DC Regulator with Internal Switches ABSOLUTE MAXIMUM RATINGS IN to SGND.............................................................-0.3V to +30V LX Current (Note 1) ....................................................-5A to +8A EN to SGND.................................................-0.3V to (V + 0.3V) Converter Output Short-Circuit Duration ...................Continuous IN LX to PGND ................................-0.3V to min (+30V, V + 0.3V) Continuous Power Dissipation (T = +70C) IN A LX to PGND .....................-1V to min (+30V, V + 0.3V) for 50ns 16-Pin TQFN (derate 14.7mW/C above +70C) IN PGOOD to SGND .....................................................-0.3V to +6V Multilayer Board .........................................................1666mW V to SGND............................................................-0.3V to +6V Operating Temperature Range ..........................-40C to +85C DD COMP, FB, SS to SGND..............-0.3V to min (+6V, V + 0.3V) Junction Temperature .....................................................+150C DD BST to LX .................................................................-0.3V to +6V Storage Temperature Range ............................-65C to +150C BST to SGND .........................................................-0.3V to +36V Lead Temperature (soldering, 10s) .................................+300C SGND to PGND ....................................................-0.3V to +0.3V Soldering Temperature (reflow) .......................................+260C Note 1: LX has internal clamp diodes to PGND and IN. Applications that forward bias these diodes should take care not to exceed the ICs package power dissipation. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. PACKAGE THERMAL CHARACTERISTICS (Note 2) 16 TQFN-EP Junction-to-Ambient Thermal Resistance ( ).........+48C/W JA Junction-to-Case Thermal Resistance ( ) ...............+7C/W JC Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four- layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS (V = 12V, C = 1F, C = 22F, T = T = -40C to +85C, typical values are at T = +25C, unless otherwise noted.) (Note 3) IN VDD IN A J A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS STEP-DOWN CONVERTER Input-Voltage Range V 4.5 28 V IN Quiescent Current I Not switching 2.1 4 mA IN V = 0V, V regulated by internal EN DD 212 LDO Shutdown Input Supply Current A V = 0V, V = V = 5V 18 28 EN IN DD ENABLE INPUT EN Shutdown Threshold Voltage V V rising 1.4 V EN SHDN EN EN Shutdown Voltage Hysteresis V 100 mV EN HYST V V rising 1.7 1.95 2.15 V EN LOCK EN EN Lockout Threshold Voltage V 100 mV EN LOCK HYST EN Input Current I V = 2.9V 2 5.3 9 A EN EN POWER-GOOD OUTPUT PGOOD Threshold V V rising 540 560 584 mV PGOOD TH FB PGOOD Threshold Hysteresis V 15 mV PGOOD HYST PGOOD Output Low Voltage V I = 5mA, V = 0.5V 35 100 mV PGOOD OL PGOOD FB PGOOD Leakage Current I V = 5V, V = 0.7V 10 nA PGOOD PGOOD FB ERROR AMPLIFIER Error Amplifier g 1.6 mS MV Transconductance Error Amplifier Voltage Gain A 90 dB VEA FB Set-Point Accuracy V 600 606 612 mV FB 2 MAX15041