MAX1714 19-1536 Rev 2 8/05 High-Speed Step-Down Controller for Notebook Computers General Description Features The MAX1714 pulse-width modulation (PWM) controller Ultra-High Efficiency provides the high efficiency, excellent transient No Current-Sense Resistor (Lossless I ) LIMIT response, and high DC output accuracy needed for Quick-PWM with 100ns Load-Step Response stepping down high-voltage batteries to generate low- voltage CPU core or chip-set/RAM supplies in notebook 1% V Accuracy Over Line and Load OUT computers. 2.5V/3.3V Fixed or 1V to 5.5V Adjustable Output Maxims proprietary Quick-PWM quick-response, Range constant-on-time PWM control scheme handles wide 2V to 28V Battery Input Range input/output voltage ratios with ease and provides 200/300/450/600kHz Switching Frequency 100ns instant-on response to load transients while Overvoltage Protection (MAX1714A) maintaining a relatively constant switching frequency. Undervoltage Protection The MAX1714 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in 1.7ms Digital Soft-Start traditional current-mode PWMs. Efficiency is further Drives Large Synchronous-Rectifier FETs enhanced by an ability to drive very large synchronous- 2V 1% Reference Output rectifier MOSFETs. Power-Good Indicator Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest Ordering Information possible efficiency. Alternatively, two-stage conversion (stepping down the +5V system supply instead of the PART TEMP RANGE PIN-PACKAGE battery) at a higher switching frequency allows the mini- MAX1714AEEP -40C to +85C 20 QSOP mum possible physical size. MAX1714AEEP+ -40C to +85C 20 QSOP The MAX1714 is intended for CPU core, chipset, MAX1714BEEE -40C to +85C 16 QSOP DRAM, or other low-voltage supplies as low as 1V. The MAX1714A is available in a 20-pin QSOP package and MAX1714BEEE+ -40C to +85C 16 QSOP includes overvoltage protection. The MAX1714B is +Denotes lead-free package. available in a 16-pin QSOP package with no overvolt- age protection. For applications requiring VID compli- Minimal Operating Circuit ance or DAC control of output voltage, refer to the MAX1710/MAX1711 data sheet. For a dual output ver- BATTERY sion, refer to the MAX1715 data sheet. 4.5V TO 28V +5V INPUT Applications V V CC DD Notebook Computers SHDN V+ CPU Core Supply BST ILIM Chipset/RAM Supply as Low as 1V OUTPUT DH 1.25V TO 2V 1.8V and 2.5V I/O Supply MAX1714 LX REF DL PGOOD PGND (GND) FB OUT SKIP AGND Quick-PWM is a trademark of Maxim Integrated Products. (GND) Future productcontact factory for availability. ( ) ARE FOR THE MAX1714B ONLY. Pin Configurations appear at end of data sheet. 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 AVAILABLEHigh-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 V , V to AGND (Note 1).....................................-0.3V to +6V REF Short Circuit to AGND.........................................Continuous DD CC PGND to AGND (Note 1) ................................................... 0.3V Continuous Power Dissipation (T = +70C) A SHDN, PGOOD, OUT to AGND (Note 1)..................-0.3V to +6V 16-Pin QSOP (derate 8.3mW/C above +70C)..........667mW ILIM, FB, REF, SKIP, 20-Pin QSOP (derate 9.1mW/C above +70C)..........727mW TON to AGND (Notes 1, 2)....................-0.3V to (V + 0.3V) Operating Temperature Range ..........................-40C to +85C CC DL to PGND (Note 1)..................................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C DD BST to AGND (Note 1) ...........................................-0.3V to +36V Storage Temperature Range ............................-65C to +150C DH to LX.....................................................-0.3V to (BST + 0.3V) Lead Temperature (soldering, 10s) .................................+300C 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, V = V = +5V, SKIP = AGND, 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 CC, DD FB = OUT 0.99 1.0 1.01 Error Comparator Threshold V+ = 4.5V to 28V, (DC Output Voltage Accuracy) FB = AGND 2.475 2.5 2.525 V SKIP = V CC (Note 3) FB = V 3.267 3.3 3.333 CC Load Regulation Error 9 mV I = 0 to 3A, SKIP = V LOAD CC Line Regulation Error V = 4.5V to 5.5V, V+ = 4.5V to 28V 5 mV CC FB Input Bias Current -0.1 0.1 A OUT Input Resistance FB = AGND 100 190 300 k Soft-Start Ramp Time Rising edge of SHDN to full I 1.7 ms LIM TON = AGND (600kHz) 140 160 180 V+ = 24V, TON = REF (450kHz) 175 200 225 On-Time V = 2V ns OUT TON = unconnected (300kHz) 260 290 320 (Note 4) TON = V (200kHz) 380 425 470 CC Minimum Off-Time (Note 4) 400 500 ns Quiescent Supply Current (V ) FB forced above the regulation point 550 750 A CC Quiescent Supply Current (V ) FB forced above the regulation point <1 5 A DD Quiescent Supply Current (V+) 25 40 A Shutdown Supply Current (V ) = 0 <1 5 A CC V SHDN Shutdown Supply Current (V ) = 0 <1 5 A DD V SHDN Shutdown Supply Current (V+) = 0 , V+ = 28V, V = V = 0 or 5V <1 5 A V CC DD SHDN Reference Voltage V = 4.5V to 5.5V, no external REF load 1.98 2 2.02 V CC Reference Load Regulation I = 0 to 50A 0.01 V REF REF Sink Current REF in regulation 10 A REF Fault Lockout Voltage Falling edge, hysteresis = 40mV 1.6 V 2 MAX1714