MAX1717 19-1636 Rev 3 8/05 Dynamically Adjustable, Synchronous Step-Down Controller for Notebook CPUs General Description Features The MAX1717 step-down controller is intended for core Quick-PWM Architecture CPU DC-DC converters in notebook computers. It fea- 1% V Accuracy Over Line and Load OUT tures a dynamically adjustable output, ultra-fast tran- 5-Bit On-Board DAC with Input Mux sient response, high DC accuracy, and high efficiency needed for leading-edge CPU core power supplies. Precision-Adjustable V Slew Control OUT Maxims proprietary Quick-PWM quick-response, 0.925V to 2V Output Adjust Range constant-on-time PWM control scheme handles wide Supports Voltage-Positioned Applications input/output voltage ratios with ease and provides 100ns instant-on response to load transients while 2V to 28V Battery Input Range maintaining a relatively constant switching frequency. Requires a Separate +5V Bias Supply The output voltage can be dynamically adjusted 200/300/550/1000kHz Switching Frequency through the 5-bit digital-to-analog converter (DAC) Over/Undervoltage Protection inputs over a 0.925V to 2V range. A unique feature of the MAX1717 is an internal multiplexer (mux) that Drives Large Synchronous-Rectifier FETs accepts two 5-bit DAC settings with only five digital 700A (typ) I Supply Current CC input pins. Output voltage transitions are accomplished 2A (typ) Shutdown Supply Current with a proprietary precision slew-rate control that mini- mizes surge currents to and from the battery while 2V 1% Reference Output guaranteeing just-in-time arrival at the new DAC setting. VGATE Transition-Complete Indicator High DC precision is enhanced by a two-wire remote- Small 24-Pin QSOP Package sensing scheme that compensates for voltage drops in the ground bus and output voltage rail. Alternatively, Ordering Information the remote-sensing inputs can be used together with the MAX1717s high DC accuracy to implement a volt- PART TEMP RANGE PIN-PACKAGE age-positioned circuit that modifies the load-transient MAX1717EEG -40C to +85C 24 QSOP response to reduce output capacitor requirements and MAX1717EEG+ -40C to +85C 24 QSOP full-load power dissipation. + Denotes lead-free package. Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest Minimal Operating Circuit possible efficiency. Alternatively, two-stage conversion (stepping down the +5V system supply instead of the battery) at a higher switching frequency allows the mini- BATTERY 2.5V TO 28V mum possible physical size. +5V INPUT MAX1717 The MAX1717 is available in a 24-pin QSOP package. V V CC DD V+ SKP/SDN Applications FBS BST Notebook Computers with SpeedStep or ILIM DH Other Dynamically Adjustable Processors GNDS OUTPUT 2-Cell to 4-Cell Li+ Battery to CPU Core Supply A/B 0.925V TO 2V Converters REF 5V to CPU Core Supply Converters LX TON CC DL D0 Pin Configuration appears at end of data sheet. GND D1 P. DAC D2 INPUTS FB Quick-PWM is a trademark of Maxim Integrated Products. D3 TIME SpeedStep is a trademark of Intel Corp. D4 VGATE Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLEDynamically Adjustable, Synchronous Step-Down Controller for Notebook CPUs ABSOLUTE MAXIMUM RATINGS V+ to GND..............................................................-0.3V to +30V LX to BST..................................................................-6V to +0.3V V , V to GND .....................................................-0.3V to +6V REF Short Circuit to GND...........................................Continuous CC DD D0D4, A/B, VGATE, to GND ..................................-0.3V to +6V Continuous Power Dissipation SKP/SDN to GND ...................................................-0.3V to +16V 24-Pin QSOP (derate 9.5mW/C above +70C)..........762mW ILIM, FB, FBS, CC, REF, GNDS, TON, Operating Temperature Range ..........................-40C to +85C TIME to GND ..........................................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C CC DL to GND..................................................-0.3V to (V + 0.3V) Storage Temperature.........................................-65C to +150C DD BST to GND............................................................-0.3V to +36V Lead Temperature (soldering, 10s) .................................+300C DH to LX .....................................................-0.3V to (BST + 0.3V) 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 = SKP/SDN = +5V, V = 1.6V, T = 0C to +85C, unless otherwise noted.) CC DD OUT A PARAMETER CONDITIONS MIN TYP MAX UNITS PWM CONTROLLER Battery voltage, V+ 228 Input Voltage Range V V , V 4.5 5.5 CC DD V+ = 4.5V to 28V, DAC codes from 1.3V to 2V -1 1 % DC Output Voltage Accuracy includes load (Note 1) regulation error DAC codes from 0.925V to 1.275V -1.2 1.2 % Remote Sense Voltage Error FB to FBS or GNDS to GND = 0 to 25mV 3 mV Line Regulation Error V = 4.5V to 5.5V, V = 4.5V to 28V 5 mV CC BATT FB Input Resistance 115 180 265 k FBS Input Bias Current -0.2 0.2 A GNDS Input Bias Current -1 1 A 150kHz nominal, R = 120k -8 +8 TIME TIME Frequency Accuracy 380kHz nominal, R = 47k -12 +12 % TIME 38kHz nominal, R = 470k -12 +12 TIME V+ = 5V, FB = 2V, TON = GND (1000kHz) 375 425 475 TON = REF (550kHz) 135 155 173 On-Time (Note 2) ns V+ = 24V, FB = 2V TON = open (300kHz) 260 289 318 TON = V (200kHz) 375 418 461 CC Minimum Off-Time (Note 2) TON = V , open, or REF (200kHz, 300kHz, or 550kHz) 400 500 ns CC Minimum Off-Time (Note 2) TON = GND (1000kHz) 300 375 ns BIAS AND REFERENCE Quiescent Supply Current (V ) Measured at V , FB forced above the regulation point 700 1200 A CC CC Quiescent Supply Current (V ) Measured at V , FB forced above the regulation point <1 5 A DD DD Quiescent Battery Supply 25 40 A Current (V+) Shutdown Supply Current (V ) SKP/SDN = 0 25 A CC Shutdown Supply Current (V ) <1 5 A SKP/SDN = 0 DD Shutdown Battery Supply SKP/SDN = 0, V = V = 0 or 5V <1 5 A CC DD Current (V+) Reference Voltage V = 4.5V to 5.5V, no REF load 1.98 2 2.02 V CC 2 MAX1717