MAX1715 19-1541 Rev 2 8/05 Ultra-High Efficiency, Dual Step-Down Controller for Notebook Computers General Description Features The MAX1715 PWM controller provides the high effi- Ultra-High Efficiency ciency, excellent transient response, and high DC out- No Current-Sense Resistor (lossless I ) LIMIT put accuracy needed for stepping down high-voltage batteries to generate low-voltage CPU core, I/O, and Quick-PWM with 100ns Load-Step Response chipset RAM supplies in notebook computers. 1% V Accuracy over Line and Load OUT Maxims proprietary Quick-PWM quick-response, constant-on-time PWM control scheme handles wide Dual-Mode Fixed 1.8V/3.3V/Adj or 2.5V/Adj Outputs input/output voltage ratios with ease and provides Adjustable 1V to 5.5V Output Range 100ns instant-on response to load transients while maintaining a relatively constant switching frequency. 2V to 28V Battery Input Range The MAX1715 achieves high efficiency at a reduced 200/300/420/540kHz Nominal Switching Frequency cost by eliminating the current-sense resistor found in Over/Undervoltage Protection traditional current-mode PWMs. Efficiency is further enhanced by its ability to drive very large synchronous- 1.7ms Digital Soft-Start rectifier MOSFETs. Drives Large Synchronous-Rectifier FETs Single-stage buck conversion allows this device to directly step down high-voltage batteries for the highest Power-Good Indicator possible efficiency. Alternatively, two-stage conversion (stepping down the +5V system supply instead of the Ordering Information battery) at a higher switching frequency allows the mini- mum possible physical size. PART TEMP RANGE PIN-PACKAGE The MAX1715 is intended for CPU core, chipset, MAX1715EEI -40C to +85C 28 QSOP DRAM, or other low-voltage supplies as low as 1V. The MAX1715 is available in a 28-pin QSOP package. For MAX1715EEI+ -40C to +85C 28 QSOP applications requiring VID compliance or DAC control + Denotes lead-free package. of output voltage, refer to the MAX1710/MAX1711 data sheet. For a single-output version, refer to the MAX1714 data sheet. Minimal Operating Circuit Applications Notebook Computers 5V INPUT BATTERY CPU Core Supply 4.5V TO 28V V V+ DD Chipset/RAM Supply as Low as 1V V CC 1.8V and 2.5V I/O Supply MAX1715 ILIM1 ILIM2 ON1 ON2 BST1 BST2 OUTPUT1 OUTPUT2 DH1 DH2 1.8V 2.5V LX1 LX2 Pin Configuration appears at end of data sheet. DL1 DL2 TON PGND OUT1 OUT2 PGOOD SKIP REF FB1 AGND FB2 Quick-PWM is a trademark of Maxim Integrated Products. 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. EVALUATION KIT AVAILABLEUltra-High Efficiency, Dual Step-Down Controller for Notebook Computers ABSOLUTE MAXIMUM RATINGS V+ to AGND..............................................................-0.3 to +30V LX1 to BST1..............................................................-6V to +0.3V V , V to AGND..................................................-0.3V to +6V LX2 to BST2..............................................................-6V to +0.3V DD CC PGND to AGND or V to V ...........................................0.3V REF Short Circuit to AGND.........................................Continuous CC DD PGOOD, OUT to AGND..........................................-0.3V to +6V Continuous Power Dissipation (T = +70C) A ILIM , FB , REF, SKIP, TON, 28-Pin QSOP (derate 8.0mW/C above +70C).....640mW/C ON to AGND...........................................-0.3V to (V + 0.3V) Operating Temperature Range ..........................-40C to +85C DD DL to PGND..............................................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C DD BST to AGND........................................................-0.3V to +36V Storage Temperature Range ............................-65C to +150C DH1 to LX1 ...............................................-0.3V to (BST1 + 0.3V) Lead Temperature (soldering, 10s) .................................+300C DH2 to LX2 ...............................................-0.3V to (BST2 + 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, 4A components from Table 1, V V = +5V, SKIP = AGND, V+ = 15V, T = 0C to +85C, unless otherwise CC = DD A noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS Battery voltage, V+ 228 Input Voltage Range V V V 4.5 5.5 DD, CC FB1 = OUT1 0.99 1.00 1.01 V+ = 2V to 28V, Output 1 Error Comparator Threshold (DC Output Voltage SKIP = V , T = +25C FB1 = AGND 1.782 1.8 1.818 V CC A Accuracy) (Note 2) I = 0 to 4A LOAD FB1 = V 3.267 3.3 3.333 CC 0.985 1.00 1.105 FB1 = OUT1 V+ = 2V to 28V, Output 1 Error Comparator Threshold (DC Output Voltage SKIP = V , T = 0C to +85C FB1 = AGND 1.773 1.8 1.827 V CC A Accuracy) (Note 2) I = 0 to 4A LOAD FB1 = V 3.250 3.3 3.350 CC Output 2 Error Comparator V+ = 2V to 28V, FB2 = OUT2 0.99 1.00 1.01 Threshold (DC Output Voltage SKIP = V , T = +25C V CC A Accuracy) (Note 2) I = 0 to 4A FB2 = GND 2.475 2.5 2.525 LOAD Output 2 Error Comparator V+ = 2V to 28V, FB2 = OUT2 0.985 1.00 1.105 Threshold (DC Output Voltage SKIP = V , T = 0C to +85C V CC A Accuracy) (Note 2) FB2 = GND 2.463 2.5 2.538 I = 0 to 4A LOAD Load Regulation Error I = 0 to 4A, each output 0.4 % LOAD Line Regulation Error V = 4.5V to 5.5V, V+ = 4.5V to 28V 0.2 % CC Output Voltage Range Adjustable mode, each output 1 5.5 V OUT Input Resistance FB = AGND 75k FB Input Bias Current V = AGND -0.1 0.1 A OUT Soft-Start Ramp Time Rising edge of ON to full current limit 1.7 ms TON = GND 112 136 160 TON = REF 142 173 205 On-Time (PWM1) V+ = 24V, OUT1 = 2V ns TON = open 210 247 280 TON = V 300 353 407 DD TON = GND 154 182 215 TON = REF 198 234 270 On-Time (PWM2) V+ = 24V, OUT2 = 2V ns TON = open 292 336 380 TON = V 420 484 550 DD 2 MAX1715