MAX1570 19-2526 Rev 1 4/05 White LED Current Regulator with 1x/1.5x High-Efficiency Charge Pump General Description Features The MAX1570 fractional charge pump drives up to five Excellent 0.3% LED-to-LED Current Matching white LEDs with regulated constant current for uniform 30mA/LED Drive Capability intensity. The MAX1570 maintains the highest possible efficiency over the full 1-cell lithium-ion (Li+) battery Proprietary 1x/1.5x Modes for Ultra-High input voltage range by utilizing a 1x/1.5x fractional Efficiency charge pump and very-low-dropout current regulators. Low Input Ripple and EMI The MAX1570 operates with 1MHz fixed-frequency switching, allowing for tiny external components. The Eliminates Ballast Resistors regulation scheme is optimized to ensure low EMI and Digital or PWM LED Dimming Control low input ripple. An external resistor sets the full-scale LED current, 0.1A Shutdown Current while two digital inputs control on/off and select 2.7V to 5.5V Supply Voltage Range between three levels of brightness. A pulse-width mod- ulation (PWM) signal can also be used to modulate LED Soft-Start Limits Inrush Current brightness. Thermal-Shutdown Protection The MAX1570 is available in 16-pin 4mm 4mm Thin No External Inductor, Schottky, or Zener Diode QFN packaging (0.8mm max height). Required Tiny 16-Pin 4mm 4mm Thin QFN Package Applications 2 White LED Backlighting Cell Phones and Smart Phones Ordering Information PDA and Palmtop Computers PART TEMP RANGE PIN-PACKAGE Portable MP3 Players MAX1570ETE -40C to +85C 16 Thin QFN Digital Cameras and Camcorders Pin Configuration Typical Operating Circuit TOP VIEW 1F1F 12 11 10 9 C1P C1N C2P C2N 2.7V TO 5.5V OUT IN 1x/1.5x REGULATING CHARGE PUMP IN 13 8 LED1 4.7F 1F LED2 C2P 14 7 MAX1570 LED1 MAX1570 EN1 15 6 ON/OFF OUT LED3 LED2 REFERENCE AND EN2 LOW-DROPOUT LED3 AND DIMMING CURRENT SET 16 5 CONTROL C2N LED4 LED4 REGULATORS LED5 R SET 12 3 4 GND PGND THIN QFN 4mm x 4mm 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. C1N C1P EN2 PGND GND EN1 LED5 SETWhite LED Current Regulator with 1x/1.5x High-Efficiency Charge Pump ABSOLUTE MAXIMUM RATINGS IN, OUT, EN1, EN2 to GND......................................-0.3V to +6V Continuous Power Dissipation (T = +70C) A SET, LED1, LED2, LED3, LED4, 16-Pin Thin QFN (derate 16.9 mW/C).......................1349mW LED5 to GND ...........................................-0.3V to (V + 0.3V) Operating Temperature Range ...........................-40C to +85C IN PGND to GND..........................................................-0.3 to +0.3V Junction Temperature......................................................+150C C1N, C2N to GND ..........................................-0.3V to (V + 1V) Storage Temperature Range .............................-65C to +150C IN C1P, C2P to GND..........................................-0.3V to the greater Lead Temperature (soldering, 10s) .................................+300C (V + 1V) or (V + 1V) OUT IN OUT Short Circuit to GND..............................................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 = 3.6V, GND = PGND = 0, EN1 = EN2 = IN, C = C1 = C2 = 1F, C = 4.7F, T = 0C to +85C, unless otherwise noted. IN IN OUT A Typical values are at T = +25C.) A PARAMETER CONDITIONS MIN TYP MAX UNITS IN Operating Voltage 2.7 5.5 V Undervoltage Lockout Threshold V rising or falling 2.25 2.45 2.60 V IN Undervoltage Lockout Hysteresis 35 mV Supply Current 1MHz switching, no load 2.0 3.5 mA Shutdown Supply Current EN1 = EN2 = GND 0.1 5 A Soft-Start Done Time 2.1 ms EN1 = GND, EN2 = IN, I = 33A 0.190 0.200 0.210 SET SET Bias Voltage EN1 = IN, EN2 = GND, I = 67A 0.380 0.400 0.420 V SET EN1 = IN, EN2 = IN, I = 100A 0.570 0.600 0.630 SET SET Leakage in Shutdown EN1 = EN2 = GND, V = 5.5V, V = 0 or 5.5V 0.01 1.00 A IN SET SET Current Range 20 130 A SET to LED Current Ratio I /I , I = 67A, V = 1V 215 230 245 A/A LED SET SET LED LED to LED Current Matching I = 67A, V = 1V -3 0.3 +3 % SET LED Maximum LED Sink Current I = 130A, V = 1V 28 30 mA SET LED I = 33A (Note 1) 100 180 SET LED Dropout Voltage I = 67A (Note 2) 200 360 mV SET I = 100A (Note 2) 230 410 SET EN1 = GND, EN2 = IN, I = 33A 185 200 215 SET LED1 Regulation Voltage EN1 = IN, EN2 = GND, I = 67A 277 300 323 mV SET (1.5x Mode) EN1 = IN, EN2 = IN, I = 100A 360 400 440 SET LED Leakage in Shutdown EN1 = GND, EN2 = GND, V = 5.5V 0.01 1.00 A LED Maximum OUT Current IN 3.4V, OUT 3.9V 150 mA 1x mode (V - V )/I 1.00 1.75 IN OUT OUT Open-Loop OUT Resistance 1.5x mode (1.5V - V )/I 8 IN OUT OUT Switching Frequency 1 MHz EN1, EN2 High Voltage IN = 2.7V to 5.5V 1.6 V EN1, EN2 Low Voltage IN = 2.7V to 5.5V 0.4 V EN1, EN2 Input Current EN = GND or 5.5V 0.01 1.00 A 2 MAX1570