MAX1572 19-2837 Rev 1 11/04 800mA, 2MHz, PWM DC-to-DC Step-Down Converter with RESET General Description Features Up to 97% Efficiency The MAX1572 is a fixed-frequency, synchronous step- down DC-to-DC converter to power low-voltage micro- 2MHz PWM Switching processor/DSP cores in portable equipment requiring 800mA Guaranteed Output Current high efficiency in a limited PC board area. The features Low 48A Quiescent Current are optimized for high efficiency over a wide load range, small external component size, low output ripple, and Power-Saving Modes: Pulse-Group, Pulse-Skip, excellent transient response. The input supply voltage Forced-PWM Mode range is from 2.6V to 5.5V, while the output is internally 0.75V to 2.5V Preset Output Range fixed from 0.75V to 2.5V in 50mV increments with a (in 50mV Increments) guaranteed output current of 800mA. The high 2MHz Voltage-Positioning Load Transients switching allows tiny low-cost capacitors and a low-pro- 5mV Output Ripple P-P file inductor, while the power-saving pulse-group mode reduces quiescent current to 48A (typ) with light loads. Tiny 2.2H Inductor To reduce noise and RF interference, the converter can 10F Ceramic Output Capacitor be configured to provide forced-PWM operation. Low 0.1A Shutdown Current The MAX1572 includes a low on-resistance internal No External Schottky Diode Required MOSFET switch and synchronous rectifier to maximize Soft-Start with Zero Inrush Current efficiency and minimize external component count. No external diode is needed. Other features include soft- 170ms (min) RESET Output start to eliminate inrush current at startup and a 170ms Small 12-Pin, 4mm x 4mm Thin QFN Package (min) RESET output to provide power-on/undervoltage Ordering Information reset. The MAX1572 is available in a 12-pin, 4mm x 4mm thin QFN package with exposed paddle. PART TEMP RANGE PIN-PACKAGE MAX1572ETC075 -40C to +85C 12 Thin QFN-EP** Applications MAX1572ETC130 -40C to +85C 12 Thin QFN-EP** Cell Phones and Smart Phones MAX1572ETC150 -40C to +85C 12 Thin QFN-EP** PDAs, Palmtops, and Notebook Computers MAX1572ETC180 -40C to +85C 12 Thin QFN-EP** MP3 and DVD Players MAX1572ETC250 -40C to +85C 12 Thin QFN-EP** MAX1572ETCxyz* -40C to +85C 12 Thin QFN-EP** Digital Cameras and Camcorders *xyz is for the output voltage (e.g., MAX1572ETC165 has a PCMCIA Cards 1.65V output). Minimum order quantity is 2500. Hand-Held Instruments **EP = Exposed paddle. Selector Guide appears at end of data sheet. Typical Operating Circuit Pin Configuration OUTPUT TOP VIEW INPUT 0.75V TO 2.5V 2.2H 2.6V TO 5.5V 800mA BATT LX 9 8 7 EN1 10 6 EN2 MAX1572 ABATT PGND GND 11 5 GND MAX1572 12 4 OUT ABATT EN1 OUT MODE 1 2 3 SELECT EN2 RESET SS GND 4mm x 4mm THIN QFN 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 AVAILABLE RESET BATT SS LX PGND GND800mA, 2MHz, PWM DC-to-DC Step-Down Converter with RESET ABSOLUTE MAXIMUM RATINGS Operating Temperature Range ...........................-40C to +85C ABATT, BATT, EN1, EN2, RESET, OUT, Junction Temperature......................................................+150C SS to GND ............................................................-0.3V to +6V PGND to GND .......................................................-0.3V to +0.3V Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C LX Current (Note 1).............................................................2.1A Output Short-Circuit Duration ............................................Infinite Continuous Power Dissipation (T = +70C) A 12-Pin Thin QFN (derate 16.9mW/C above +70C)...1349mW Note 1: LX has internal clamp diodes to PGND and BATT. Applications that forward bias these diodes should take care not to exceed the ICs package power dissipation limits. 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 (V = 3.6V, T = +0C to +85C, unless otherwise noted. Typical values are at T = +25C.) BATT A A PARAMETER CONDITIONS MIN TYP MAX UNITS BATT Input Voltage 2.6 5.5 V Undervoltage Lockout Threshold V rising and falling, 1% hysteresis 2.20 2.35 2.55 V BATT EN1 = GND, EN2 = BATT, no switching 48 80 Quiescent Supply Current A EN1 = BATT, EN2 = GND, no switching 700 Shutdown Supply Current EN1 = EN2 = GND, T = +25C 0.1 1 A A Maximum Output Current 800 mA OUT Bias Current 69 A No load, EN1 = EN2 = BATT 1.2 2.7 100mA load -0.4 +0.8 +2.0 Output-Voltage Accuracy 300mA load 0 % (Voltage Positioning) 550mA load -1 800mA load -2 Line Regulation 0.3 %/V V = 3.6V 0.28 0.45 BATT P-Channel On-Resistance I = 180mA LX V = 2.6V 0.33 BATT V = 3.6V 0.18 0.30 BATT N-Channel On-Resistance I = 180mA LX V = 2.6V 0.20 BATT P-Channel Current-Limit Threshold 1.00 1.25 1.65 A N-Channel Current-Limit Threshold EN1 = EN2 = BATT -0.68 -0.52 -0.37 A N-Channel Zero-Crossing Threshold EN1 = BATT, EN2 = GND 15 40 65 mA LX Output Current (Note 2) 1.4 A RMS LX Leakage Current EN1 = EN2 = GND 0.1 10 A Maximum Duty Cycle 100 % EN1 = BATT, EN2 = GND or 0 EN1 = GND, EN2 = BATT Minimum Duty Cycle % EN1 = EN2 = BATT 16.7 17.3 Switching Frequency 1.8 2 2.2 MHz SS Output Impedance 65 100 150 k 2 MAX1572