MAX1714AEEP+T

19-1536; Rev 2; 8/05 KIT ATION EVALU E L B AVAILA High-Speed Step-Down Controller for Notebook Computers The MAX1714 pulse-width modulation (PWM) controller provides the high efficiency, excellent transient response, and high DC output accuracy needed for stepping down high-voltage batteries to generate lowvoltage CPU core or chip-set/RAM supplies in notebook computers. Maxim’s proprietary Quick-PWM™ quick-response, constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency. The MAX1714 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by an ability to drive very large synchronousrectifier MOSFETs. Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the +5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size. The MAX1714 is intended for CPU core, chipset, DRAM, or other low-voltage supplies as low as 1V. The MAX1714A is available in a 20-pin QSOP package and includes overvoltage protection. The MAX1714B is available in a 16-pin QSOP package with no overvoltage protection. For applications requiring VID compliance or DAC control of output voltage, refer to the MAX1710/MAX1711 data sheet. For a dual output version, refer to the MAX1715† data sheet. Features ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ Ultra-High Efficiency No Current-Sense Resistor (Lossless ILIMIT) Quick-PWM with 100ns Load-Step Response 1% VOUT Accuracy Over Line and Load 2.5V/3.3V Fixed or 1V to 5.5V Adjustable Output Range 2V to 28V Battery Input Range 200/300/450/600kHz Switching Frequency Overvoltage Protection (MAX1714A) Undervoltage Protection 1.7ms Digital Soft-Start Drives Large Synchronous-Rectifier FETs 2V ±1% Reference Output Power-Good Indicator Ordering Information PART TEMP RANGE PIN-PACKAGE MAX1714AEEP -40°C to +85°C 20 QSOP MAX1714AEEP+ -40°C to +85°C 20 QSOP MAX1714BEEE -40°C to +85°C 16 QSOP MAX1714BEEE+ -40°C to +85°C +Denotes lead-free package. 16 QSOP Minimal Operating Circuit BATTERY 4.5V TO 28V +5V INPUT Applications Notebook Computers VCC SHDN VDD V+ ILIM BST CPU Core Supply Chipset/RAM Supply as Low as 1V OUTPUT 1.25V TO 2V DH 1.8V and 2.5V I/O Supply MAX1714 LX REF DL PGOOD PGND (GND) FB OUT SKIP Quick-PWM is a trademark of Maxim Integrated Products. † Future product—contact factory for availability. Pin Configurations appear at end of data sheet. AGND (GND) ( ) ARE FOR THE MAX1714B ONLY. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX1714 General Description MAX1714 High-Speed Step-Down Controller for Notebook Computers ABSOLUTE MAXIMUM RATINGS V+ to AGND (Note 1)..............................................-0.3V to +30V LX to BST..................................................................-6V to +0.3V VDD, VCC to AGND (Note 1) .....................................-0.3V to +6V REF Short Circuit to AGND.........................................Continuous PGND to AGND (Note 1) ................................................... ±0.3V Continuous Power Dissipation (TA = +70°C) SHDN, PGOOD, OUT to AGND (Note 1)..................-0.3V to +6V 16-Pin QSOP (derate 8.3mW/°C above +70°C)..........667mW ILIM, FB, REF, SKIP, 20-Pin QSOP (derate 9.1mW/°C above +70°C)..........727mW TON to AGND (Notes 1, 2)....................-0.3V to (VCC + 0.3V) Operating Temperature Range ..........................-40°C to +85°C DL to PGND (Note 1)..................................-0.3V to (VDD + 0.3V) Junction Temperature ......................................................+150°C BST to AGND (Note 1) ...........................................-0.3V to + 36V Storage Temperature Range ............................-65°C to +150°C DH to LX.....................................................-0.3V to (BST + 0.3V) Lead Temperature (soldering, 10s) .................................+300°C Note 1: For the MAX1714B, AGND and PGND refer to a single pin designated GND. Note 2: SKIP may be forced below -0.3V, temporarily exceeding the absolute maximum rating, disabling over/undervoltage fault detection for the purpose of debugging prototypes (Figure 6). Limit the current drawn to 5mA maximum. 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+ = +15V, VCC = VDD = +5V, SKIP = AGND, TA = 0°C to +85°C, unless otherwise noted.) (Note 1) PARAMETER Input Voltage Range CONDITIONS Battery voltage, V+ VCC, VDD 2 28 4.5 5.5 1.0 1.01 FB = AGND 2.475 2.5 2.525 FB = VCC 3.267 3.3 3.333 Load Regulation Error ILOAD = 0 to 3A, SKIP = VCC Line Regulation Error VCC = 4.5V to 5.5V, V+ = 4.5V to 28V 9 FB = AGND Soft-Start Ramp Time Rising edge of SHDN to full ILIM V+ = 24V, VOUT = 2V (Note 4) UNITS V V mV 5 -0.1 OUT Input Resistance MAX 0.99 V+ = 4.5V to 28V, SKIP = VCC FB Input Bias Current mV 0.1 µA 300 kΩ 100 190 TON = AGND (600kHz) 140 160 180 TON = REF (450kHz) 175 200 225 TON = unconnected (300kHz) 260 290 320 TON = VCC (200kHz) 380 425 470 1.7 ms ns Minimum Off-Time (Note 4) 400 500 ns Quiescent Supply Current (VCC) FB forced above the regulation point 550 750 µA Quiescent Supply Current (VDD) FB forced above the regulation point