MAX1574 19-3117 Rev 0 12/03 180mA, 1x/2x, White LED Charge Pump in 3mm x 3mm TDFN General Description Features The MAX1574 charge pump drives up to three white Up to 180mA (60mA/LED) Drive Capability LEDs with regulated constant current for uniform intensity. 83% Average Efficiency (P / P ) Over Li+ LED BATT By utilizing adaptive 1x/2x charge-pump modes and Battery Discharge very-low-dropout current regulators, it achieves 180mA output drive capability and high efficiency over the 1-cell 0.5% (typ) LED Current Matching lithium-battery input voltage range. Fixed-frequency Adaptive 1x/2x Mode Switchover (1MHz) switching allows for tiny external components, and the regulation scheme is optimized to ensure low EMI Low Input Ripple and EMI and low input ripple. 5% to 100% Dimming Through Single-Wire Serial The MAX1574 uses an external resistor to set the full- Pulse Interface scale 100% LED current. An enable input (EN) is used for simple on/off control or can be pulsed repeatedly to set Low 0.1A Shutdown Current lower LED current in multiple steps down to 5%. Once the 2.7V to 5.5V Supply Voltage Range desired brightness is set, the MAX1574 maintains con- stant LED current as long as EN is kept high. If EN is kept Soft-Start Limits Inrush Current low for more than 2ms, the MAX1574 enters shutdown. Output Overvoltage Protection The MAX1574 is available in a 10-pin 3mm x 3mm TDFN Thermal-Shutdown Protection package (0.8mm max height). 10-Pin 3mm x 3mm TDFN Package Applications Ordering Information LCD Backlighting PIN- TOP PART TEMP RANGE PACKAGE MARK Camera Strobes/Flashes and Movie Lights Cell Phones/Smart Phones 10 TDFN MAX1574ETB -40C to +85C ABB 3mm x 3mm PDAs, Digital Cameras, and Camcorders Typical Operating Circuit Pin Configuration 0.22F TOP VIEW CP CN 10 9 8 7 6 2.7V TO 5.5V UP TO 180mA IN OUT 1F 1F MAX1574 GND MAX1574 LED1 ON/OFF AND EN DIMMING LED2 12 3 44 5 SET LED3 TDFN 3mm 3mm 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 AVAILABLE IN OUT EN GND CP LED1 CN LED2 SET LED3180mA, 1x/2x, White LED Charge Pump in 3mm x 3mm TDFN ABSOLUTE MAXIMUM RATINGS IN, OUT, EN to GND..............................................-0.3V to +6.0V Continuous Power Dissipation (T = +70C) A SET, LED1, LED2, LED3, CN to GND .........-0.3V to (V + 0.3V) 10-Pin TDFN (derate 18.2mW/C above +70C) .......1454mW IN CP to GND ......................................................................-0.3V to Operating Temperature Range ...........................-40C to +85C the greater of (V + 1V) or (V + 1V) Junction Temperature......................................................+150C OUT IN OUT Short Circuit to GND ..........................................Continuous Storage Temperature Range .............................-65C to +150C 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 = 3.6V, V = 0V, EN = IN, R = 13.7k, T = -40C to +85C, unless otherwise noted. Typical values are at T = +25C.) IN GND SET A A (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS IN Operating Voltage 2.7 5.5 V Undervoltage-Lockout Threshold V falling 2.25 2.45 2.60 V IN Undervoltage-Lockout Hysteresis 40 mV Output Overvoltage-Protection Threshold V rising 5 V OUT 2x mode 2 No-Load Supply Current mA 10% setting, 1x mode 0.35 EN = GND, T = +25C 0.01 1 A Shutdown Supply Current A EN = GND, T = +85C 0.1 A Soft-Start Time 2ms SET Bias Voltage 0.6 V EN = GND, T = +25C 0.01 1 A SET Leakage in Shutdown A EN = GND, T = +85C 0.1 A SET Current Range 4 153 A SET-to-LED Current Ratio (I /I ) 100% setting 393 A/A LED SET LED Current Accuracy T = +25C 0.7 % A LED-to-LED Current Matching (Note 2) -4 0.5 +4 % Maximum LED Sink Current R = 4.12k 52 60 mA SET LED Dropout Voltage R = 4.12k (Note 3) 80 120 mV SET 1x to 2x Mode Transition Threshold V falling 120 130 140 mV LED Input-Voltage-Mode Transition Hysteresis 150 mV EN = GND, T = +25C 0.01 2 A LED Leakage in Shutdown A EN = GND, T = +85C 0.1 A Maximum OUT Current V 3.12V, V = 3.9V 180 mA IN OUT 1x mode, (V - V ) / I 1.5 2.5 IN OUT OUT Open-Loop OUT Resistance 2x mode, (2 x V - V ) / I 915 IN OUT OUT Switching Frequency 1 MHz OUT Pulldown Resistance in Shutdown EN = GND 5 k EN High Voltage V = 2.7V to 5.5V 1.6 V IN EN Low Voltage V = 2.7V to 5.5V 0.4 V IN 2 MAX1574