MAX1813 19-2010 Rev 0 4/01 Dynamically-Adjustable, Synchronous Step-Down Controller with Integrated Voltage Positioning General Description Features The MAX1813 step-down controller is intended for core High-Efficiency Voltage Positioning CPU DC-DC converters in notebook computers. The Quick-PWM Architecture controller features a dynamically adjustable output (5- bit DAC), ultra-fast transient response, high DC accura- 1% V Accuracy Over Line OUT cy, and high efficiency necessary for leading-edge Adjustable Output Slew Rate CPU core power supplies. Maxims proprietary Quick- PWM quick-response, constant-on-time PWM control 0.600V to 2V Adjustable Output Range (5-Bit DAC) scheme handles wide input/output voltage ratios with 2V to 28V Battery Input Range ease and provides 100ns instant-on response to load transients while maintaining a relatively constant switch- 200/300/600/1000kHz Switching Frequency ing frequency. Output Undervoltage and Overvoltage Protection The MAX1813 is designed specifically for CPU core applications requiring a voltage-positioned supply. The Drives Large Synchronous-Rectifier MOSFETs voltage-positioning input (VPCS), combined with a 20% Accurate Current-Limit high-DC-accuracy control loop, is used to implement a power supply that modifies its output set point in 10A Shutdown Supply Current response to the load current. This arrangement 2V 1% Reference Output decreases full-load power dissipation and reduces the required number of output capacitors. Power-Good (PGOOD) Indicator The output voltage can be dynamically adjusted Small 28-Pin QSOP Package through the 5-bit digital-to-analog converter (DAC) inputs over a 0.600V to 2V range. The MAX1813 Ordering Information includes an internal multiplexer that selects between three different DAC code settings. The first two inputs PART TEMP. RANGE PIN-PACKAGE are controlled by five digital input pins (D0D4). The MAX1813EEI -40C to +85C 28 QSOP third input is used for the suspend mode and controlled by two 4-level input pins (S0, S1). Output voltage transi- tions are accomplished with a proprietary precision Pin Configuration slew-rate control that minimizes surge currents to and from the battery while guaranteeing just-in-time arrival TOP VIEW at the new DAC setting. V+ 1 28 DH VPCS 2 27 LX The MAX1813s 28V input range enables single-stage buck conversion from high-voltage batteries for the SKP/SDN 3 26 BST maximum possible efficiency. Alternatively, the con- TIME 4 25 D0 trollers high-frequency capability combined with two- FB 5 24 D1 stage conversion (stepping down the +5V system MAX1813 CC 6 23 D2 supply instead of the battery) allows the smallest possi- S0 7 22 D3 ble physical size. S1 8 21 D4 The MAX1813 is available in a 28-pin QSOP package. V 9 20 CODE CC Applications TON 10 19 ZMODE Notebook Computers REF 11 18 SUS (Intel IMVPII/Coppermine) ILIM 12 17 V DD PGOOD 13 16 DL Docking Stations GND 14 15 PGND CPU Core Supply QSOP Single-Stage (BATT to V ) Converters CORE Two-Stage (+5V to V ) Converters CORE Quick-PWM is a trademark of Maxim Integrated Products, Inc. Typical Operating Circuit appears at end of data sheet. Coppermine and IMVP- are trademarks of Intel Corp. Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.Dynamically-Adjustable, Synchronous Step-Down Controller with Integrated Voltage Positioning ABSOLUTE MAXIMUM RATINGS V+ to GND..............................................................-0.3V to +30V DH to LX....................................................-0.3V to (V + 0.3V) BST V , V to GND .....................................................-0.3V to +6V LX to BST..................................................................-6V to +0.3V CC DD PGND to GND.....................................................................0.3V REF Short Circuit to GND...........................................Continuous D0D4, CODE, ZMODE, SUS, PGOOD to GND ......-0.3V to +6V Continuous Power Dissipation (T = +70C) A SKP/SDN to GND (Note 1) .....................................-0.3V to +16V 28-Pin QSOP (derate 10.8mW/C above +70C)..........860mW ILIM, FB, CC, REF, Operating Temperature Range ...........................-40C to +85C TON, TIME, S0, S1 to GND......................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C CC VPCS to GND ............................................................-2V to +30V Storage Temperature Range .............................-65C to +150C DL to PGND................................................-0.3V to (V + 0.3V) DD Lead Temperature (soldering, 10s) .................................+300C BST to PGND..........................................................-0.3V to +36V Note 1: SKP/SDN may be forced to 12V, temporarily exceeding the absolute maximum rating, for the purpose of debugging proto- type breadboards, using the no-fault test mode. 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 (Circuit of Figure 1, V+ = +15V, V = V = 5V, VPCS = ZMODE = GND = PGND, SKP/SDN = CODE = V , V set to 1.5V, CC DD CC OUT T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS PWM CONTROLLER Battery voltage, V+ 2 28 Input Voltage Range V V , V 4.5 5.5 CC DD V+ = 4.5V to 28V, VPCS = GND, DAC -1 +1 codes from 0.925V to 2.0V DC Output Voltage Accuracy V+ = 4.5V to 28V, VPCS = GND, DAC -1.5 +1.5 % (Notes 2, 3) codes from 0.700V to 0.900V V+ = 4.5V to 28V, VPCS = GND, DAC -1.83 +1.83 codes from 0.600V to 0.675V VPCS Input Bias Current I V = 0 or 28V -1 +1 A VPS VPCS VPCS Transconductance G V = 0 to -100mV 18 20 22 S m VPCS VPCS Linear Input Range 100 mV FB Input Resistance R 115 180 265 k FB 38kHz nominal, R = 470k -12 +12 TIME TIME Frequency Accuracy 150kHz nominal, R = 120k -8 +8 % TIME 380kHz nominal, R = 47k -12 +12 TIME ILIM Input Leakage Current I V = 0 or 5.0V 0.01 100 nA ILIM ILIM V+ = 5.0V, V = 1.2V TON = GND 250 270 290 FB TON = REF 165 190 215 On-Time (Note 4) t ns ON V+ = 12V, V = 1.2V TON = open 320 355 390 FB TON = V 465 515 563 CC TON = REF, open, or V 400 500 CC Minimum Off-Time (Note 4) t ns OFF(MIN) TON = GND 300 375 BIAS AND REFERENCE Measured at V , FB forced above the CC Quiescent Supply Current (V)I 1.4 2.5 mA CC CC regulation point 2 MAX1813