EVALUATION KIT AVAILABLE High-Efficiency, 40V Step-Up MAX1553/MAX1554 Converters for 2 to 10 White LEDs General Description Benefits and Features The MAX1553/MAX1554 drive white LEDs in series with Highly Integrated and Flexible Solution for Wide a constant current to provide efficient display backlight- Range of Backlighting Applications ing in cellular phones, PDAs, and other hand-held Constant-Current Regulation for Even LED devices. The step-up converter includes an internal Illumination 40V, low R , N-channel MOSFET switch for high DSON Internal 40V MOSFET Switch Capable of Driving efficiency and maximum battery life. The MAX1553 has 10 LEDs a current limit of 480mA for driving two to six white 2.7V to 5.5V Input Voltage Range LEDs, while the MAX1554 has a current limit of 970mA Analog or PWM Control of LED Intensity for driving up to 10 white LEDs. Optimized for Low Input Ripple A single analog/PWM Dual Mode input provides two Soft-Start Minimizes Inrush Current simple means of brightness adjustment. A separate High Efficiency Improves Battery Life enable input provides on/off control. Soft-start mini- Up to 88% Efficiency Driving 6 LEDs mizes inrush current during startup. Up to 82% Efficiency Driving 9 LEDs (20mA, The MAX1553/MAX1554 are available in space-saving V = 3.6V) CC 8-pin TDFN 3mm x 3mm packages. Tiny 8-Pin, 3mm x 3mm TDFN Package Saves Space Small, Low-Profile External Components Applications Cellular Phones PDA, Palmtop, and Wireless Handhelds Ordering Information Color Display Backlight TOP PART TEMP RANGE PIN-PACKAGE MARK M A X15 5 3 E TA -40C to +85C 8 TDFN 3m m x 3mm AGX M A X15 5 4 E TA -40C to +85C 8 TDFN 3m m x 3mm AGY Dual Mode is a trademark of Maxim Integrated Products, Inc. Typical Operating Circuit Pin Configuration TOP VIEW 2.7V TO 5.5V INPUT V LX CC WHITE GND 1 8 LX ON LEDS EN OV OFF V 2 7 0V CC MAX1553 MAX1553 6 EN 3 MAX1554 SS MAX1554 PWM 4 5 FB BRT OR BRT FB DC CONTROL SS GND TDFN 3mm x 3mm 19-2875 Rev 2 5/15High-Efficiency, 40V Step-Up MAX1553/MAX1554 Converters for 2 to 10 White LEDs Absolute Maximum Ratings V , FB, OV to GND..............................................-0.3V to +6.0V Operating Temperature Range ...........................-40C to +85C CC LX to GND ..............................................................-0.3V to +45V Junction Temperature......................................................+150C EN, BRT, SS to GND...................................-0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +150C CC I ...................................................................................0.9A Lead Temperature (soldering, 10s) .................................+300C LX RMS Continuous Power Dissipation (T = +70C) A 8-Pin 3mm x 3mm TDFN (derate 24.4mW/C above +70C).............................1951mW 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 = 0V, C = 1F, R = 10, T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) CC OV OUT SENSE A A PARAMETER CONDITIONS MIN TYP MAX UNITS MAX1553 2.7 5.5 Supply Voltage V MAX1554 3.15 5.50 Undervoltage Lockout Threshold V rising or falling, 35mV hysteresis typical 2.35 2.5 2.65 V CC Not switching 0.33 0.65 Quiescent Current mA Switching 0.44 0.9 T = +25C 0.1 1 A Shutdown Supply Current V = 0V A EN T = +85C 1 A OV Threshold Rising edge 1.18 1.25 1.33 V T = +25C 1 200 A OV Input Bias Current V = 1V nA OV T = +85C 10 A BRT Input Resistance 0 < V < 1.5V, EN = V 200 400 600 k BRT CC TIMING CONTROL Maximum On-Time V = 3.3V 2.0 3.4 4.8 s CC On-Time Constant (K) t = K / V 6.3 s-V ON CC Minimum Off-Time 150 250 350 ns ERROR AMPLIFIER V = 1.25V 192 203 212 BRT FB Threshold mV V = 3.3V 280 BRT T = +25C 15 200 A FB Input Bias Current V = 1.0V nA FB T = +85C 100 A N-CHANNEL SWITCH LX On-Resistance 0.8 1.4 www.maximintegrated.com Maxim Integrated 2