MAX1606 19-1744 Rev 1 1/04 28V Internal Switch LCD Bias Supply with True Shutdown General Description Features The MAX1606 is a step-up DC-DC converter that con- Adjustable Output Voltage up to 28V tains a 0.5A internal power switch and a 0.5A output 20mA at 20V from a Single Li+ Battery isolation switch in an 8-pin MAX package. The IC operates from a 2.4V to 5.5V supply voltage but can True Shutdown (Output Disconnected from Input) boost battery voltages as low as 0.8V up to 28V. Output Short-Circuit Protection The MAX1606 uses a unique control scheme that pro- vides high efficiency over a wide range of load condi- 88% Efficiency tions. An internal 0.5A MOSFET reduces external Up to 500kHz Switching Frequency component count, and a high switching frequency (up to 500kHz) allows for tiny surface-mount components. Selectable Inductor Current Limit The current limit can be set to 500mA, 250mA, or (125mA, 250mA, or 500mA) 125mA, allowing the user to reduce the output ripple 0.1A Shutdown Current and component size in low-current applications. 8-Pin MAX Package Additional features include a low quiescent supply cur- rent and a true shutdown mode that saves power by disconnecting the output from the input. The MAX1606 is ideal for small LCD panels with low current require- ments but can also be used in other applications. A MAX1606 evaluation kit is available to help speed up design time. Applications Ordering Information LCD Bias Generators PART TEMP RANGE PIN-PACKAGE Cellular or Cordless Phones MAX1606EUA -40C to +85C8 MAX Palmtop Computers Personal Digital Assistants (PDAs) Organizers Handy Terminals Typical Operating Circuit Pin Configuration TOP VIEW SW V = V TO 28V V = 0.8V TO 5.5V OUT IN IN LX BATT BATT 1 8 SW MAX1606 FB 2 7 SHDN MAX1606 V = 2.4V TO 5.5V CC V 3 6 LIM CC V CC FB GND 4 5 LX LIM ON MAX OFF SHDN GND 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 1-800-835-8769.28V Internal Switch LCD Bias Supply with True Shutdown ABSOLUTE MAXIMUM RATINGS V , FB, BATT, SW to GND .....................................-0.3V to +6V Continuous Power Dissipation (T = +70C) CC A BATT to SW ..............................................................-0.3V to +6V 8-Pin MAX (derate 4.1mW/C above +70C).............330mW SHDN, LIM to GND.....................................-0.3V to (V + 0.3V) Operating Temperature Range ...........................-40C to +85C CC LX to GND ..............................................................-0.3V to +30V Junction Temperature......................................................+150C Current into LX or BATT..............................................600mA Storage Temperature Range .............................-65C to +150C RMS Current out of SW .......................................................600mA Lead Temperature (soldering, 10s) .................................+300C RMS Output Short-Circuit Duration ........................................Indefinite 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 = 3.3V, V = BATT = SHDN, T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) CC CC A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS V Supply Voltage V (Note 1) 2.4 5.5 V CC CC BATT Input Voltage Range V (Note 1) 0.8 5.5 V BATT V Undervoltage Lockout V V falling, 30mV typical hysteresis 2.0 2.2 2.37 V CC UVLO CC V Quiescent Supply Current I V = 1.3V 160 320 A CC CC FB V Shutdown Supply Current SHDN = GND 0.1 1 A CC BATT Input Supply Current I V = 1.3V 20 40 A BATT FB BATT Shutdown Supply Current SHDN = GND 0.1 1 A V = 18V, I = 1mA, V = 3.6V, OUT LOAD BATT V Line Regulation V 0.1 %/V CC LNR V = V = 2.4V to 5.5V CC LIM V = 18V, I = 1mA, OUT LOAD BATT Line Regulation V 0.05 %/V LNR V = V = 3.3V, V = 0.8V to 5.5V CC LIM BATT V = 18V, V = V = V = 3.3V, OUT CC BATT LIM Load Regulation V 0.05 %/mA LDR I = 0mA to 20mA LOAD Efficiency L1 = 100H, V = 3.6V, I = 10mA 88 % BATT LOAD Feedback Set Point V 1.225 1.25 1.275 V FB Feedback Input Bias Current I V = 1.3V 5 100 nA FB FB INDUCTOR CONNECTIONS (LX, SW) LX Voltage Range V 28 V LX LIM = V 0.40 0.50 0.56 CC LX Switch Current Limit I LIM = floating 0.20 0.25 0.285 A LX(MAX) LIM = GND 0.10 0.125 0.15 V = 5V, I = 100mA 0.8 CC LX LX On-Resistance R LX V = 3.3V, I = 100mA 1 2 CC LX LX Leakage Current V = 28V 2 A LX Maximum LX On-Time t 10 13 16 s ON V > 1.1V 0.8 1.0 1.2 FB Minimum LX Off-Time t s OFF V < 0.8V (soft-start) 3.9 5.0 6.0 FB SW Leakage Current SW = GND, V = 5.5V 1 BATT A 2 MAX1606