MAX1561/MAX1599 19-2731 Rev 1 10/03 High-Efficiency, 26V Step-Up Converters for Two to Six White LEDs General Description Features The MAX1561/MAX1599 step-up converters drive up to Accurate Current Regulation for Uniform six white LEDs with a constant current to provide back- Illumination light in cell phones, PDAs, and other hand-held High Efficiency Up to 87% devices. The step-up converter topology allows series Flexible Analog or PWM Dimming Control connection of the white LEDs so the LED currents are identical for uniform brightness. This configuration elim- Up to 900mW Output Power with Internal 30V inates the need for ballast resistors and expensive fac- MOSFET Switch tory calibration. Fast 1MHz (MAX1561) or 500kHz (MAX1599) PWM The MAX1561/MAX1599 include an internal, high-volt- Operation age, low-R N-channel MOSFET switch for high DS(ON) Small, Low-Profile External Components efficiency and maximum battery life. A single Dual 2.6V to 5.5V Input Range Mode input provides a simple means of brightness adjustment and on/off control. Fast 1MHz (500kHz for 26V (max) Output with Overvoltage Protection the MAX1599) current-mode, pulse-width modulated Optimized for Low 15mV Input Ripple P-P (PWM) operation allows for small input and output Soft-Start with Zero Inrush Current capacitors and a small inductor while minimizing ripple on the input supply/battery. Programmable soft-start 0.3A Shutdown Current eliminates inrush current during startup. Tiny 8-Pin 3mm x 3mm Thin DFN Package Both devices are available in a space-saving, 8-pin 3mm x 3mm thin DFN package with exposed paddle (EP). Ordering Information Applications TOP PART TEMP RANGE PIN-PACKAGE Cell Phones and Smart Phones MARK PDAs, Palmtops, and Wireless Handhelds 8 TDFN-EP* MAX1561ETA -40C to +85C ACS e-Books and Subnotebooks 8 TDFN-EP* MAX1599ETA -40C to +85C AHG White LED Display Backlighting *EP = Exposed paddle. Typical Operating Circuit Pin Configuration INPUT 2.6V TO 5.5V TOP VIEW OUTPUT UP TO 6 LEDs LX IN MAX1561 MAX1599 OUT 1 8 LX OUT MAX1561 2 7 PGND IN MAX1599 3 6 GND CTRL PWM OR ANALOG CTRL PGND CS 4 5 COMP DIMMING 3mm 3mm THIN DFN COMP CS GND Dual Mode is a trademark of Maxim Integrated Products, Inc. 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 AVAILABLEHigh-Efficiency, 26V Step-Up Converters for Two to Six White LEDs ABSOLUTE MAXIMUM RATINGS IN to GND.................................................................-0.3V to +6V Continuous Power Dissipation (T = +70C) A PGND to GND .......................................................-0.3V to +0.3V 3mm x 3mm 8-Pin TDFN LX, OUT to GND.....................................................-0.3V to +30V (derate 24.4mW/C above +70C).............................1950mW CTRL to GND...................-0.3V to the lower of +6V or (V + 2V) Operating Temperature Range ...........................-40C to +85C IN COMP, CS to GND.........................................-0.3 to (V + 0.3V) Junction Temperature......................................................+150C IN I .............................................................................................1A Storage Temperature Range .............................-65C to +150C LX Lead Temperature (soldering, 10s) .................................+300C 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 = 3V, V = 20V, C = 0.1F, C = 0.15F, R = 7.5, V = 1.5V, Figure 1, T = 0C to +85C, unless other- IN OUT OUT COMP SENSE CTRL A wise noted. Typical values are at T = +25C.) A PARAMETER CONDITIONS MIN TYP MAX UNITS Supply Voltage 2.6 5.5 V UVLO Threshold V rising or falling 2.10 2.38 2.55 V IN UVLO Hysteresis 40 mV Quiescent Current No switching 0.38 0.55 mA T = +25C 0.3 2 A Shutdown Supply Current CTRL = GND, V = V A OUT IN T = +85C1 A OVLO Threshold V rising 26 27 29 V OUT OVLO Hysteresis 2V V = 26V, V > 0.24V 10 20 30 OUT CTRL OUT Input Bias Current A V = V , CTRL = GND 0.01 1 OUT IN Output Voltage Range (Note 1) (V - V ) 25.5 V IN D1 ERROR AMPLIFIER CTRL to CS Regulation V = 1V, V = 2.6V to 5.5V 0.095 0.100 0.105 V CTRL IN T = +25C 0.01 1 A CS Input Bias Current V = V /10 A CS CTRL T = +85C 0.03 A CTRL Input Resistance V 1.0V 290 500 780 k CTRL CTRL Dual-Mode Threshold 100 170 240 mV CTRL Dual-Mode Hysteresis 5mV MAX1561 6.5 8.2 10.5 CTRL Shutdown Enable Delay (Note 2) ms MAX1599 13.6 16.4 21.0 CS-to-COMP Transconductance V = 1.0V 32 50 82 S COMP OSCILLATOR MAX1561 0.80 1.0 1.25 Operating Frequency MHz MAX1599 0.4 0.5 0.6 PWM mode 12 Minimum Duty Cycle % Pulse skipping 0 Maximum Duty Cycle CTRL = IN, CS = GND 91 94 % 2 MAX1561/MAX1599