MAX1522/MAX1523/MAX1524 19-1926 Rev 1 8/10 Simple SOT23 Boost Controllers General Description Features The MAX1522/MAX1523/MAX1524 are simple, compact Simple, Flexible Application Circuit boost controllers designed for a wide range of DC-DC 2-Cell NiMH or Alkaline Operation (MAX1524) conversion topologies, including step-up, SEPIC, and flyback applications. They are for applications where Low Quiescent Current (25A typ) extremely low cost and small size are top priorities. These devices are designed specifically to provide a Output Fault Protection and Soft-Start simple application circuit and minimize the size and High Efficiency Over 1000:1 I Range OUT number of external components, making them ideal for PDAs, digital cameras, and other low-cost consumer Pin-Selectable Maximum Duty Factor electronics applications. Micropower Shutdown Mode These devices use a unique fixed on-time, minimum off- Small 6-Pin SOT23 Package time architecture, which provides excellent efficiency over a wide-range of input/output voltage combinations No Current-Sense Resistor and load currents. The fixed on-time is pin selectable to either 0.5s (50% max duty cycle) or 3s (85% max Ordering Information duty cycle), permitting optimization of external compo- nent size and ease of design for a wide range of output PIN- TOP voltages. PART TEMP. RANGE PACKAGE MARK The MAX1522/MAX1523 operate from a +2.5V to +5.5V MAX1522EUT-T -40C to +85C 6 SOT23 AAOX input voltage range and are capable of generating a wide range of outputs. The MAX1524 is intended for MAX1523EUT-T -40C to +85C 6 SOT23 AAOY bootstrapped operation, permitting startup with lower MAX1524EUT-T -40C to +85C 6 SOT23 AAOZ input voltage. All devices have internal soft-start and MAX1522EUT+T -40C to +85C 6 SOT23 +AAOX short-circuit protection to prevent excessive switching current during startup and under output fault condi- MAX1523EUT+T -40C to +85C 6 SOT23 +AAOY tions. The MAX1522/MAX1524 have a latched fault MAX1524EUT+T -40C to +85C 6 SOT23 +AAOZ mode, which shuts down the controller when a short- +Denotes a lead(Pb)-free/RoHS-compliant package. circuit event occurs, whereas the MAX1523 reenters -Denotes a package containing lead(Pb). soft-start mode during output fault conditions. The T = Tape and reel. MAX1522/MAX1523/MAX1524 are available in a space- saving 6-pin SOT23 package. Typical Operating Circuit Applications Low-Cost, High-Current, Low-Cost, Multi-Output or High-Voltage Boost Flyback Converters INPUT Conversion SEPIC Converters LCD Bias Supplies Low-Cost Battery- Industrial +24V and +28V Powered Applications Power Supplies OUTPUT V CC Pin Configuration 5 EXT N 6 V CC TOP VIEW GND16 V MAX1522 CC 3 2 MAX1523 FB 50% 85% SET MAX1524 MAX1522 4 1 FB 2 5 EXT MAX1523 GND OFF ON SHDN MAX1524 SET34 SHDN SOT23 Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLESimple SOT23 Boost Controllers ABSOLUTE MAXIMUM RATINGS V , FB, SHDN, SET to GND ...................................-0.3V to +6V Junction Temperature......................................................+150C CC EXT to GND ................................................-0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +150C CC Continuous Power Dissipation (T = +70C) Lead Temperature (soldering, 10s) ................................+300C A 6-Pin SOT23 (derate 8.7mW/C above +70C) ..........696mW Soldering Temperature (reflow) ......................................+260C Operating Temperature Range ..........................-40C to +85C 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 = SHDN = 3.3V, SET = GND , T = -40C to +85C, unless otherwise noted. Typical values are at T = +25C.) CC A A PARAMETER CONDITIONS MIN TYP MAX UNITS V Operating Voltage Range 2.5 5.5 V CC MAX1522/MAX1523 2.5 V Minimum Startup Voltage V CC f > 100kHz, MAX1524 (Note 1), bootstrap required 1.5 EXT V rising 2.37 2.47 Undervoltage Lockout CC V Threshold V falling 2.20 2.30 CC V Supply Current No load, nonbootstrapped 25 50 A CC V Shutdown Current SHDN = GND 0.001 1 A CC SET = GND 0.4 0.5 0.6 Fixed t Time V =1.2V s ON FB SET = V 2.4 3.0 3.6 CC V > 0.675V 0.5 FB Minimum t Time s OFF V < 0.525V 1.0 FB SET = GND 45 50 55 Maximum Duty Factor % SET = V 80 85 90 CC FB Regulation Threshold V = +2.5V to +5.5V 1.23 1.25 1.27 V CC (Note 2) FB Undervoltage Fault FB falling 525 575 625 mV Threshold (Note 2) FB Input Bias Current V = 1.3V 6 50 nA FB EXT high 2 4 EXT Resistance I = 20mA EXT EXT low 1.5 3 Soft-Start Ramp Time 2.2 3.2 4.2 ms Logic Input High V = +2.5V to +5.5V, SET, SHDN 1.6 V CC Logic Input Low V = +2.5V to +5.5V, SET, SHDN 0.4 V CC Logic Input Leakage Current SET, SHDN = V or GND -1 +1 A CC Note 1: Actual startup voltage is dependent on the external MOSFETs V . GS(TH) Note 2: Specification applies after soft-start mode is completed. 2 MAX1522/MAX1523/MAX1524