MAX8822 19-0847 Rev 0 11/07 Ultra-Efficient Negative Charge-Pump LED Driver with Dual LDOs in 3mm x 3mm Thin QFN General Description Features The MAX8822 drives up to four white light-emitting High-Efficiency Charge Pump for Up to Four diodes (LEDs) with regulated constant current for dis- White LEDs play backlighting in cell phones, digital cameras, PDAs, Independent Adaptive Voltage Supply for Each and other handheld devices. By utilizing a proprietary LED negative 0.5x inverting charge pump and innovative 24mA to 0.1mA Dimming Range independent low-dropout (LDO) adaptive current regu- 1% (typ) Current Accuracy and 0.3% Current lators, very high efficiency is achieved over the full Matching 1-cell Li+ battery voltage range, even with large LED V Low 65A (typ) Quiescent Current F mismatch. The 1MHz fixed-frequency switching allows Dual 200mA Low-Noise, High PSRR LDOs for tiny external components. The regulation scheme is 16 Different Output Voltage Combinations Up to optimized to ensure low EMI and low input ripple. Two 3.3V 200mA, low-noise, high power-supply-rejection-ratio High 60dB PSRR at 10kHz (PSRR) LDOs with programmable output voltages are Flexible Single-Wire Control for Dimming and included on-chip to provide power to camera modules LDO Output Voltage or other devices. Low 0.5A (typ) Shutdown Mode The MAX8822 features a single-wire, serial-pulse control- logic interface that programs LED current and the output Soft-Start Limits Inrush Current voltages of the LDOs. The LED dimming range is pseu- Thermal Shutdown and Open- and Short-Circuit do-logarithmic from 24mA to 0.1mA in 31 steps. LDO Protection output voltages are programmable in 16 different combi- Tiny 16-Pin, 3mm x 3mm Thin QFN Package nations to meet various camera module requirements. (0.8mm max Height) with Exposed Paddle The MAX8822 includes soft-start, thermal shutdown, open- and short-circuit protection. Ordering Information Applications White LED Backlighting PKG PART PIN-PACKAGE TOP MARK CODE Cell Phones and Smartphones 16 Thin QFN-EP* MAX8822ETE+ AFW T1633-5 Typical Operating Circuit (3mm x 3mm) Note: The device is specified over the -40C to +85C extend- INPUT 2.7V TO 5.5V ed temperature range. +Denotes a lead-free package. 1F 1F *EP = Exposed paddle. C1P C1N C2P C2N Pin Configuration TOP VIEW LED1 IN LED2 12 11 10 9 4.7F MAX8822 LED3 GND LDO2 13 8 LED4 LED4 UP TO 24mA/LED 14 7 NEG ENLED ENLED NEG SERIAL- MAX8822 PULSE ENLDO 15 6 C1N 2.2F CONTROL INTERFACE ENLDO 16 5 C2N REF REF V LDO1 + LDO1 132 4 0.1F V LDO2 LDO2 EP 1F 1F THIN QFN (3mm x 3mm) Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim s website at www.maxim-ic.com. EVALUATION KIT AVAILABLE IN LDO1 GND LED1 C1P LED2 C2P LED3Ultra-Efficient Negative Charge-Pump LED Driver with Dual LDOs in 3mm x 3mm Thin QFN ABSOLUTE MAXIMUM RATINGS IN, C1N, C2N, REF, ENLED, ENLDO, LDO1, LDO2 Continuous Power Dissipation (T = +70C) A to GND...............................................................-0.3V to +6.0V 16-Pin Thin QFN 3mm x 3mm IN, REF, ENLED, ENLDO, LDO1, LDO2 (derate 14.7mW/C above +70C).............................1177mW to NEG...............................................................-0.3V to +6.0V Operating Temperature Range ...........................-40C to +85C LED , C1N, C2N to NEG .............................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C IN C1P, C2P to GND ........................................-0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +150C IN NEG to GND..........................................................-6.0V to +0.3V Lead Temperature (soldering, 10s) .................................+300C NEG, LDO1, LDO2 Short-Circuit Current to GND......Continuous 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, T = -40C to +85C, unless otherwise noted. Typical values are at T = +25C.) (Note 1) IN GND A A PARAMETER CONDITIONS MIN TYP MAX UNITS IN Operating Voltage 2.7 5.5 V Undervoltage Lockout (UVLO) V rising 2.25 2.45 2.65 V IN Threshold UVLO Hysteresis 100 mV T = +25C 0.5 5 A Shutdown Supply Current ENLED = ENLDO = GND A T = +85C 0.5 A Charge pump inactive, 65 100 A I = I = I = I = 0.1mA LED1 LED2 LED3 LED4 IN Operating Supply Current Charge pump active, V = 2.7V, 1MHz switching, IN 1.4 mA I = I = I = I = 0.1mA LED1 LED2 LED3 LED4 Thermal-Shutdown Threshold 160 C Thermal-Shutdown Hysteresis 20 C SERIAL-PULSE CONTROL Logic Input-High Voltage (V)V = 2.7V to 5.5V 1.4 V IH IN Logic Input-Low Voltage (V)V = 2.7V to 5.5V 0.4 V IL IN T = +25C 0.01 1 A Logic Input Current V = 0V or V = 5.5V A IL IH T = +85C 0.1 A t See Figures 1 and 2 (Note 2) 2.5 ms SHDN t See Figures 1 and 2 0.5 500 s LO t See Figures 1 and 2 0.5 500 s HI t First high pulse from shutdown (Figures 1 and 2) 100 s INIT t Pulse width to latch EN count (Figures 1 and 2) (Note 3) 2.5 ms HOLD CHARGE PUMP Switching Frequency 1 MHz Soft-Start Time 0.5 ms Charge-Pump Regulation Voltage (V - V)5V IN NEG Open-Loop NEG Output (V - 0.5 x V ) / I 2.8 5.0 NEG IN NEG Resistance NEG Shutdown Discharge All LEDs off, EN = GND 10 k Resistance 2 MAX8822