MAX639/MAX640/MAX653 19-4505 Rev 4 7/05 5V/3.3V/3V/Adjustable, High-Efficiency, Low I , Step-Down DC-DC Converters Q General Description Features The MAX639/MAX640/MAX653 step-down switching High Efficiency for a Wide Range of Load Currents regulators provide high efficiency over a wide range of 10A Quiescent Current load currents, delivering up to 225mA. A current-limiting pulse-frequency-modulated (PFM) control scheme gives Output Currents Up to 225mA the devices the benefits of pulse-width-modulated Preset or Adjustable Output Voltage: (PWM) converters (high efficiency at heavy loads), while using only 10A of supply current (vs. 2mA to 10mA for 5.0V (MAX639) PWM converters). The result is high efficiency over a 3.3V (MAX640) wide range of loads. 3.0V (MAX653) The MAX639/MAX640/MAX653 input range is 4V to Low-Battery Detection Comparator 11.5V, and the devices provide lower preset output volt- Current-Limiting PFM Control Scheme ages of 5V, 3.3V, and 3V, respectively. Or, the output can be user-adjusted to any voltage from 1.3V to the input voltage. The MAX639/MAX640/MAX653 have an internal 1A power Ordering Information MOSFET switch, making them ideal for minimum-compo- PART TEMP RANGE PIN-PACKAGE nent, low- and medium-power applications. For increased output drive capability, use the MAX649/MAX651/MAX652 MAX639CPA 0C to +70C 8 Plastic DIP step-down controllers, which drive an external P-channel MAX639CSA 0C to +70C 8 SO FET to deliver up to 5W. MAX639C/D 0C to +70C Dice* MAX639EPA -40C to +85C 8 Plastic DIP Applications MAX639ESA -40C to +85C 8 SO 9V Battery to 5V, 3.3V, or 3V Conversion MAX639MJA -55C to +125C 8 CERDIP Ordering Information continued on last page. High-Efficiency Linear Regulator Replacement *Contact factory for dice specifications. Portable Instruments and Handy-Terminals 5V-to-3.3V Converters Typical Operating Circuit Pin Configuration TOP VIEW INPUT 5.5V TO 11.5V OUTPUT 5V V+ 225mA LX VOUT 1 8 SHDN MAX639 LBO 7 2 VFB MAX639 MAX640 ON/OFF SHDN VOUT MAX653 LBI 3 6 V+ LOW-BATTERY LOW-BATTERY GND LBI 4 5 LX LBO DETECTOR DETECTOR OUTPUT INPUT DIP/SO VFB GND 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.5V/3.3V/3V/Adjustable, High-Efficiency, Low I , Step-Down DC-DC Converters Q ABSOLUTE MAXIMUM RATINGS V+...........................................................................................12V Operating Temperature Ranges: LX .........................................................(V+ - 12V) to (V+ + 0.3V) MAX639C .......................................................0C to +70C LBI, LBO, VFB, SHDN, VOUT........................-0.3V to (V+ + 0.3V) MAX639E ....................................................-40C to +85C LX Output Current (Note 1)......................................................1A MAX639MJA ..................................................-55C to +125C LBO Output Current............................................................10mA Storage Temperature Range .............................-65C to +160C Continuous Power Dissipation (T = +70C) Lead Temperature (soldering, 10s) .................................+300C A Plastic DIP (derate 9.09mW/C above +70C) .............727mW SO (derate 5.88mW/C above +70C)..........................471mW CERDIP (derate 8.00mW/C above +70C)..................640mW Note 1: Peak inductor current must be limited to 600mA by using an inductor of 100H or greater. 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+ = 9V for the MAX639, V+ = 5V for the MAX640/MAX653, I = 0mA, T = T to T , typical values are at T = +25C, LOAD A MIN MAX A unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS Supply Voltage 4.0 11.5 V Supply Current SHDN = V+, no load 10 20 A MAX639, V+ = 6.0V to 11.5V, 0mA < I < 100mA 4.80 5.00 5.20 OUT Output Voltage (Note 2) MAX640, V+ = 4.0V to 11.5V, 0mA < I < 100mA 3.17 3.30 3.43 V OUT MAX653, V+ = 4.0V to 11.5V, 0mA < I < 100mA 2.88 3.00 3.12 OUT Dropout Voltage I = 100mA, L = 100H 0.5 V OUT I = 100mA, L = 100H 91 OUT MAX639 I = 25mA, L = 470H 94 OUT I = 100mA, L = 100H 87 OUT Efficiency MAX640 % I = 25mA, L = 470H 91 OUT I = 100mA, L = 100H 85 OUT MAX653 I = 25mA, L = 470H 89 OUT V+ = 9V, V = 5V 10.6 12.5 14.4 OUT MAX639 V+ = 6V, V = 3V 14.2 16.7 19.2 OUT V+ = 9V, V = 3.3V 7.5 8.8 10.1 OUT Switch On-Time s MAX640 V+ = 4V, V = 3.3V 60.7 71.4 82.1 OUT V+ = 9V, V = 3V 7.1 8.3 9.5 OUT MAX653 V+ = 4V, V = 3V 42.5 50.0 57.5 OUT V+ = 9V, V = 5V 9.0 11.7 13.5 OUT MAX639 V+ = 6V, V = 3V 16.6 19.5 22.4 OUT V+ = 9V, V = 3.3V 13.3 15.6 17.9 OUT Switch Off-Time MAX640 s V+ = 4V, V = 3.3V 13.3 15.6 17.9 OUT V+ = 9V, V = 3V 14.6 17.2 19.8 OUT MAX653 V+ = 4V, V = 3V 14.6 17.2 19.8 OUT 2 MAX639/MAX640/MAX653