MAX1711EEG

19-4781; Rev 1; 7/00 KIT ATION EVALU E L B A AVAIL High-Speed, Digitally Adjusted Step-Down Controllers for Notebook CPUs The MAX1710/MAX1711 step-down controllers are intended for core CPU DC-DC converters in notebook computers. They feature a triple-threat combination of ultra-fast transient response, high DC accuracy, and high efficiency needed for leading-edge CPU core power supplies. 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. High DC precision is ensured by a 2-wire remote-sensing scheme that compensates for voltage drops in both the ground bus and supply rail. An on-board, digital-toanalog converter (DAC) sets the output voltage in compliance with Mobile Pentium II® CPU specifications. The MAX1710 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, 2-stage conversion (stepping down the +5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size. The MAX1710/MAX1711 are identical except that the MAX1711 have 5-bit DACs and the MAX1710 has a 4bit DAC. Also, the MAX1711 has a fixed overvoltage protection threshold at VOUT = 2.25V and undervoltage protection at VOUT = 0.8V whereas the MAX1710 has variable thresholds that track VOUT. The MAX1711 is intended for applications where the DAC code may change dynamically. Features ♦ Ultra-High Efficiency ♦ No Current-Sense Resistor (Lossless ILIMIT) ♦ Quick-PWM with 100ns Load-Step Response ♦ ±1% VOUT Accuracy over Line and Load ♦ 4-Bit On-Board DAC (MAX1710) ♦ 5-Bit On-Board DAC (MAX1711/MAX1712) ♦ 0.925V to 2V Output Adjust Range (MAX1711/MAX1712) ♦ 2V to 28V Battery Input Range ♦ 200/300/400/550kHz Switching Frequency ♦ Remote GND and VOUT Sensing ♦ Over/Undervoltage Protection ♦ 1.7ms Digital Soft-Start ♦ Drive Large Synchronous-Rectifier FETs ♦ 2V ±1% Reference Output ♦ Power-Good Indicator ♦ Small 24-Pin QSOP Package Ordering Information PART TEMP. RANGE PIN-PACKAGE MAX1710EEG -40°C to +85°C 24 QSOP MAX1711EEG -40°C to +85°C 24 QSOP Minimal Operating Circuit BATTERY 4.5V TO 28V +5V INPUT VCC Applications OVP* SHDN Notebook Computers FBS ILIM Docking Stations GNDS CPU Core DC-DC Converters VDD V+ BST DH MAX1710 MAX1711 REF MAX1712 LX Single-Stage (BATT to VCORE) Converters Two-Stage (+5V to VCORE) Converters CC OUTPUT 0.925V TO 2V (MAX1711/MAX1712) DL D0 Quick-PWM is a trademark of Maxim Integrated Products. D/A INPUTS Mobile Pentium II is a registered trademark of Intel Corp. Pin Configurations appear at end of data sheet. *MAX1710 ONLY **MAX1711/MAX1712 ONLY D1 PGND D2 FB D3 SKIP D4** GND ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX1710/MAX1711/MAX1712 General Description MAX1710/MAX1711/MAX1712 High-Speed, Digitally Adjusted Step-Down Controllers for Notebook CPUs ABSOLUTE MAXIMUM RATINGS V+ to GND ..............................................................-0.3V to +30V VCC, VDD to GND .....................................................-0.3V to +6V PGND to GND.....................................................................±0.3V SHDN, PGOOD to GND ...........................................-0.3V to +6V OVP, ILIM, FB, FBS, CC, REF, D0–D4, GNDS, TON to GND ..............................-0.3V to (VCC + 0.3V) SKIP to GND (Note 1).................................-0.3V to (VCC + 0.3V) DL to PGND................................................-0.3V to (VDD + 0.3V) BST to GND ............................................................-0.3V to +36V DH to LX .....................................................-0.3V to (BST + 0.3V) LX to BST..................................................................-6V to +0.3V REF Short Circuit to GND ...........................................Continuous Continuous Power Dissipation (TA = +70°C) 24-Pin QSOP (derate 9.5mW/°C above +70°C)..........762mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +165°C Lead Temperature (soldering, 10s) .................................+300°C Note 1: SKIP may be forced below -0.3V, temporarily exceeding the absolute maximum rating, for the purpose of debugging prototype breadboards using the no-fault test mode. 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, VBATT = 15V, VCC = VDD = 5V, SKIP = GND, TA = 0°C to +85°C, unless otherwise noted.) PARAMETER CONDITIONS MIN MAX UNIT 28 VCC, VDD 4.5 5.5 DAC codes from 1.3V to 2V VBATT = 4.5V to 28V, includes DAC codes from 0.925V load regulation error to 1.275V -1 1 DC Output Voltage Accuracy -1.2 1.2 Load Regulation Error ILOAD = 0 to 7A 9 mV Remote-Sense Voltage Error FB - FBS or GNDS - GND = 0 to 25mV 3 mV Line Regulation Error VCC = 4.5V to 5.5V, VBATT = 4.5V to 28V FB Input Bias Current FB (MAX1710 only) or FBS FB Input Resistance (MAX1711/MAX1712) 5 -0.2 130 GNDS Input Bias Current 180 -1 Soft-Start Ramp Time Rising edge of SHDN to full ILIM On-Time TON = GND (550kHz) VBATT = 24V, TON = REF (400kHz) FB = 2V TON = open (300kHz) (Note 2) TON = VCC (200kHz) Minimum Off-Time (Note 2) Quiescent Supply Current (VCC) Quiescent Supply Current (VDD) V % mV 0.2 µA 240 kΩ 1 1.7 µA ms 140 160 180 175 200 225 260 290 320 380 425 470 400 500 ns Measured at VCC, FB forced above the regulation point 600 950 µA Measured at VDD, FB forced above the regulation point