EVALUATION KIT AVAILABLE 5V/3.3V or Adjustable, MAX1626/MAX1627 100% Duty-Cycle, High-Efficiency, Step-Down DC-DC Controllers General Description Benefits and Features The MAX1626/MAX1627 step-down DC-DC controllers Reduce External Components and Total Cost operate over a 2.6V to 16.5V input voltage range. The 300KHz PWM Switching Reduces Component Size controllers deliver load current from 1mA to more than Tiny Surface-Mount Inductor 2A. The MAX1626 has pin-selectable 3.3V and 5V out- Reduce Power Dissipation puts. The MAX1627 supports adjustable outputs from > 90% Efficiency from 3mA to 2A Loads 1.3V to 16V. Low Dropout Voltage A unique current-limited, pulse-frequency-modulation 100% Maximum Duty Cycle (PFM) control scheme operates up to 100% duty cycle, Reduce Number of DC-DC Controllers to Stock resulting in very low dropout voltage. This control Wide 2.6V to 16.5V Input Voltage Options scheme eliminates minimum load requirements and Selectable 3.3V and 5V or Adjustable 1.3V to 16V reduces supply current under light loads to 90A Output Voltage Options (versus 2mA to 10mA for common pulse-width modula- tion controllers). Reduce System Power Consumption 90A Max Quiescent Current The devices are available in a 8-pin SOIC package 1A Max Shutdown Current (-40C to +85C) and dice (0C to +70C). Operates Reliably in Adverse Environment Applications Soft-Start Limits Startup Current Current-Limited Control Scheme 5V to 3.3V Green PC Applications Increase Design Flexibility Battery-Powered Applications External P-Channel MOSFET Allows Output Power Handheld Computers of > 12.5W High-Efficiency Step-Down Regulation Ordering Information Low-Cost Notebook Computer Supplies PART TEMP RANGE PIN-PACKAGE Minimum Component DC-DC Converters MAX1626C/D 0C to +70C Dice* PCMCIA Power Supplies MAX1626ESA -40C to +85C 8 SO PDAs and Other Handheld Devices MAX1627C/D 0C to +70C Dice* Portable Terminals MAX1627ESA -40C to +85C 8 SO * Dice are tested at T = +25C. A Typical Operating Circuit Pin Configuration INPUT 3.3V to 16.5V TOP VIEW V+ OUT 1 8 GND MAX1626 3/5 (FB) 2 EXT 7 MAX1626 ON/OFF SHDN CS SHDN MAX1627 3 6 CS EXT P OUTPUT REF 4 5 V+ 3.3V 3/5 SO OUT REF GND ( ) ARE FOR MAX1627 19-1075 Rev 1 5/155V/3.3V or Adjustable, MAX1626/MAX1627 100% Duty-Cycle, High-Efficiency, Step-Down DC-DC Controllers Supply Voltage, V+ to GND.......................................-0.3V, +17V Operating Temperature Range OUT, FB, 3/5, SHDN, REF, CS, EXT to GND ...-0.3V, (V+ + 0.3V) MAX1626ESA/MAX1627ESA ............................-40C to +85C Maximum Current at REF (I )..........................................15mA Storage Temperature Range .............................-65C to +160C REF Maximum Current at EXT (I ) ..........................................50mA Lead Temperature (soldering, 10sec) .............................+300C EXT Continuous Power Dissipation (T = +70C) A SO (derate 5.88mW/C above +70C)..........................471mW 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 PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Voltage Range V+ 3.0 16.5 V Operating, no load 70 90 Supply Current into V+ I+ A V+ = SHDN = 16.5V (shutdown) 1 Undervoltage Lockout 2.7 2.8 V Circuit of Figure 1, 3/5 = V+ (Note 1) 4.85 5.00 5.15 Output Voltage V V OUT 3.20 3.30 3.40 Circuit of Figure 1, 3/5 = 0V (Note 1) OUT Input Current I MAX1626, 3/5 = V+, output forced to 5V 24 37 50 A OUT FB Threshold Voltage MAX1627, includes hysteresis 1.27 1.30 1.33 V FB Leakage Current MAX1627 035 nA CS Input Current 010 A CS Threshold Voltage V 85 100 115 mV CS SHDN Input Voltage High 1.6 V SHDN Input Voltage Low 0.4 V SHDN Input Current SHDN = 0V or V+ 1 A 3/5 Input Voltage High V+ - 0.5 V 3/5 Input Voltage Low 0.5 V 1 A 3/5 Leakage Current 3/5 = 0V or V+ EXT Resistance V+ = 5V 10 Output forced to 0V 810 12 Minimum EXT Off Time s Output in regulation 1.5 2.0 2.5 EXT Duty-Cycle Limit 100 % Line Regulation 6.0V < V+ < 12.0V, I = 1A 5 mV/V LOAD Load Regulation 30mA < I < 2.0A, V+ = 8V 15 mV/A LOAD Reference Voltage V I = 0A 1.27 1.30 1.33 V REF LOAD REF Load Regulation 0A I 100A 410 mV REF REF Line Regulation V+ = 3V to 16.5V, I = 0A 10 100 V/V LOAD www.maximintegrated.com Maxim Integrated 2