MAX1716EEG+

19-1758; Rev 0; 8/00 High-Speed, Adjustable, Synchronous Step-Down Controllers with Integrated Voltage Positioning Features ♦ High-Efficiency Voltage Positioning ♦ Quick-PWM Architecture ♦ ±1% VOUT Line-Regulation Accuracy ♦ Adjustable Output Range (5-Bit DAC) MAX1716: 0.925V to 1.6V MAX1854: 0.925V to 2.0V MAX1855: 0.600V to 1.75V ♦ 2V to 28V Input Range ♦ 200/300/400/550kHz Switching Frequency ♦ Output Undervoltage Protection ♦ Overvoltage Protection (MAX1716/MAX1855) ♦ Drive Large Synchronous-Rectifier MOSFETs ♦ 1.7ms Digital Soft-Start ♦ 700µA ICC Supply Current ♦ 1µA Shutdown Supply Current ♦ 2V ±1% Reference Output ♦ VGATE Transition-Complete Indicator ♦ Small 24-Pin QSOP Package Typical Operating Circuit ________________________Applications VCC Notebook Computers Docking Stations CPU Core Supply SHDN VDD V+ ILIM BST REF DH Two-Stage (+5V to VCORE) Converters Ordering Information GND CS TON VPS D0 TEMP. RANGE PIN-PACKAGE MAX1716EEG -40°C to +85°C 24 QSOP MAX1854EEG -40°C to +85°C 24 QSOP D3 MAX1855EEG -40°C to +85°C 24 QSOP D4 Quick-PWM is a trademark of Maxim Integrated Products. SpeedStep is a trademark of Intel Corp. OUTPUT MAX1716 CC MAX1854 LX SKIP MAX1855 DL Single-Stage (BATT to VCORE) Converters PART BATTERY 2V TO 28V +5V INPUT DAC INPUTS D1 PGND D2 FB VGATE Pin Configuration appears at end of data sheet. ________________________________________________________________ Maxim Integrated Products 1 For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX1716/MAX1854/MAX1855 General Description The MAX1716/MAX1854/MAX1855 step-down controllers are intended for core CPU DC-DC converters in notebook computers. They feature a dynamically adjustable output (5-bit DAC), 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-ontime 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 MAX1716/MAX1854/MAX1855 are designed specifically for CPU core applications requiring a voltage-positioned supply. The voltage-positioning input (VPS), combined with a high DC accuracy control loop, is used to implement a power supply that modifies its output set point in response to the load current. This arrangement decreases full-load power dissipation and reduces the required number of output capacitors. The 28V input range of the MAX1716/MAX1854/MAX1855 enables single-stage buck conversion from high-voltage batteries for the maximum possible efficiency. Alternatively, the devices’ high-frequency capability combined with two-stage conversion (stepping down the +5V system supply instead of the battery) allows the smallest possible physical size. The output voltage can be dynamically adjusted through the 5-bit digitalto-analog converter (DAC) inputs. The MAX1716/MAX1854/MAX1855 are available in a 24-pin QSOP package. For applications requiring SpeedStep™ power control (see the MAX1717). MAX1716/MAX1854/MAX1855 High-Speed, Adjustable, Synchronous Step-Down Controllers with Integrated Voltage Positioning ABSOLUTE MAXIMUM RATINGS V+ to GND ..............................................................-0.3V to +30V VCC, VDD to GND .....................................................-0.3V to +6V PGND to GND.....................................................................±0.3V SHDN, VGATE to GND .............................................-0.3V to +6V ILIM, FB, CC, REF, D0–D4, VPS, 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 (VBST + 0.3V) LX to BST..................................................................-6V to +0.3V CS to GND.................................................................-2V to +30V 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 +150°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 -2mA (max). 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, VCC = VDD = 5V, SKIP = VCC, VPS = PGND, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS PWM CONTROLLER Battery voltage, V+ Input Voltage Range DC Output Voltage Accuracy (Notes 2, 3) V+ = 4.5V to 28V, VPS = PGND 28 5.5 DAC codes from 1.35V to 2.0V -1 1 DAC codes from 0.925V to 1.3V -1.2 1.2 DAC codes from 0.6V to 0.9V -1.5 1.5 -0.2 0.2 µA -1 1 µA 0.197 %/mV 1 µA 100 nA FB Input Bias Current IFB FB = 0.6V to 2.0V VPS Input Bias Current IVPS VVPS = ±40mV VPS Gain AVPS VVPS = 0 or -40mV, gain from VPS to FB CS Input Bias Current ICS 0 to 28V ILIM Input Leakage Current IILIM VILIM = 0 or 5.0V Soft-Start Ramp Time On-Time (Note 4) Minimum Off-Time (Note 4) 2 2 4.5 VCC, VDD 0.153 0.01 0 to full ILIM tON tOFF(MIN) V+ = 11.0V, VFB = 1.5V 0.175 -1 1.7 % ms TON = GND 205 255 300 TON = REF 280 327 375 TON = open 425 470 520 TON = VCC 615 678 740 400 500 _______________________________________________________________________________________ V ns ns High-Speed, Adjustable, Synchronous Step-Down Controllers with Integrated Voltage Positioning (Circuit of Figure 1, V+ = +15V, VCC = VDD = 5V, SKIP = VCC, VPS = PGND, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS BIAS AND REFERENCE Quiescent Supply Current (VCC) ICC Measured at VCC, FB forced above the regulation point 700 950 µA Quiescent Supply Current (VDD) IDD Measured at VDD, FB forced above the regulation point