MAX8686 19-4113 Rev 1 10/10 Single/Multiphase, Step-Down, DC-DC Converter Delivers Up to 25A Per Phase General Description Features The MAX8686 current-mode, synchronous PWM step- Operating Range from 4.5V to 20V Input Supply down regulator with integrated MOSFETs operates from 1% Reference Voltage Accuracy Over Temperature a 4.5V to 20V input supply and generates an adjustable Reference Input (REFIN) for Output Tracking or output voltage from 0.7V to 5.5V while delivering up to System Reference Voltage 25A per phase. The MAX8686 employs a peak current-mode architec- Adjustable Switching Frequency from 300kHz ture that operates with an adjustable switching frequency to 1MHz from 300kHz to 1MHz. An adjustable current-limit thresh- Single/Multiphase Operation Delivers Up to old allows for optimization for different applications with 25A/200A with Integrated MOSFETs different load currents. Inductor current sense is Adjustable Current Limit achieved either using an external sense resistor or using a lossless inductor current-sense scheme. The foldback Monotonic Output Voltage at Startup (Prebias) and hiccup current limit reduces the power dissipation Output Sink and Source Current Capability during overload or short-circuit conditions and allows for autorecovery when the fault condition is removed. Adjustable Soft-Start The MAX8686 offers the ability to start up monotonically Thermal-Overload Protection even when there is a prebias output voltage. In addi- Output Overvoltage Protection tion, an adjustable soft-start capability allows for a con- Thermally Enhanced 6mm x 6mm TQFN trolled turn-on. The MAX8686 features an accurate 1% Package (4W) reference and offers a reference input that allows for a higher accuracy reference to be used for voltage track- ing applications such as DDR memory. Ordering Information The MAX8686 can be paralleled (up to eight) together PART TEMP RANGE PIN-PACKAGE in a true multiphase mode to deliver up to 200A of out- MAX8686ETL+ -40C to +85C 40 TQFN-EP* put current. When operating in this mode, this device achieves better than 10% current balance between +Denotes a lead-free package. phases at full load. The MAX8686 supports program- *EP = Exposed pad. mable phase shedding to improve system efficiency during light load conditions. Typical Application Circuit Other features include an enable input and a power-OK (POK) indicator used for power sequencing. The MAX8686 also features latch overvoltage protection V = 12V IN IN BST that turns on the low-side MOSFET when the output voltage exceeds 120% of the nominal voltage. The V = 1.2V/25A OUT MAX8686 is offered in a thermally enhanced 40-pin, PGND LX 6mm x 6mm TQFN package. RS+ Applications REFIN MAX8686 RS- POL Power Supplies PHASE/REFO CS+ Module Replacements COMP CS- POK Telecom Equipment POK OUTPUT Networking Equipment EN/SLOPE Servers ENABLE INPUT DDR Memory FREQ SS GND ILIM Pin Configuration appears at end of data sheet. 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.Single/Multiphase, Step-Down, DC-DC Converter Delivers Up to 25A Per Phase ABSOLUTE MAXIMUM RATINGS IN, INA to PGND.....................................................-0.3V to +22V LX Continuous Current ....................................................25A RMS BST, DH to LX...........................................................-0.3V to +6V Continuous Power Dissipation (T = +70C) (Note 1) A BST to PGND..........................................................-0.3V to +28V 40-Pin TQFN (derate 50mW/C above +70C) ..........4000mW LX to PGND...........................-0.3V to (V + 0.3V) (-2V for 50ns) (thermal resistance from junction to exposed pad) IN JC BST to VL................................................................-0.3V to +22V (Note 1) ......................................................................3.5C/W AVL to GND.................................................-0.3V to (V + 0.3V) (thermal resistance from junction to top) (Note 1) ...3.9C/W VL JT COMP, ILIM, FREQ, PHASE/REFO, RS+, RS-, POK, REFIN, Operating Temperature Range ...........................-40C to +85C CS+, CS- to GND ..................................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C AVL VL to PGND ..............................................................-0.3V to +6V Storage Temperature Range .............................-65C to +150C EN/SLOPE to GND ...................................................-0.3V to +6V Lead Temperature (soldering, 10s) .................................+300C RTN to PGND to GND to GFREQ ..........................-0.3V to +0.3V Soldering Temperature (reflow) .......................................+260C IN Continuous Current.....................................................20A RMS Note 1: 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 see www.maxim-ic.com/thermal-tutorial. 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. ELECTRICAL CHARACTERISTICS (V = V = 12V, VL = AVL, V = 1V, V - V = 1V, V = 0V, V = 1.25V, V = V = 1V, R = 122k, C = 1F, IN INA REFIN RS+ RS- RS- EN/SLOPE CS+ CS- ILIM VL C = 0.22F, C = 270pF, T = +25C, unless otherwise noted.) (Note 2) AVL FREQ A PARAMETER CONDITIONS MIN TYP MAX UNITS GENERAL Operating Input-Voltage Range V = V , T = -40C to +85C 6 20 V INA IN A Operating Input-Voltage Range V = V = V = V , T = -40C to +85C 4.5 5.5 V IN INA VL AVL A T = +25C 450 V = 0V, A EN/SLOPE IN/INA Shutdown Supply Current A V = V = 20V IN INA T = +85C 500 A V = 1.1V, no switching V = V = 20V, RS+ IN INA IN/INA Quiescent Supply Current 5.5 6.6 mA T = -40C to +85C A Rising, T = -40C to +85C 4.2 4.35 4.45 AVL Undervoltage Lockout Trip A V Level Falling 4.03 6V V = V 20V, 1mA I 30mA, IN INA VL VL Output Voltage 5.2 5.4 5.5 V T = -40C to +85C A SOFT-START (SS) SS Shutdown Resistance V = 0V (master mode) 20 100 EN/SLOPE SS Soft-Start Current V = 0.4V and 1.1V, T = -40C to +85C 19 25 31 A SS A PHASE COMPARATOR AND REFERENCE (PHASE/REFO) Measured at PHASE/REFO (master mode), Reference Output Voltage 3.267 3.300 3.333 V T = -40C to +85C A V = V (slave mode), V = 0.3V and 2.5V, RS- AVL PHASE PHASE Comparator Offset -20 +20 mV T = -40C to +85C A REFIN INPUT REFIN Input Bias Current V = 0.7V or 3.3V -500 +500 nA REFIN REFIN Input Voltage Range 0 3.3 V 2 MAX8686