19-2847; Rev 2; 8/05 White LED 1x/1.5x Charge Pump inUCSP and Thin QFNMAX1573General DescriptionFeatures The MAX1573 fractional charge pump drives up to four ♦ Proprietary Adaptive 1x/1.5x Modes white LEDs with regulated constant current for uniform ♦ High Efficiency (PLEDs/PBATT), Up to 92% intensity. By utilizing proprietary adaptive 1x/1.5x modes and ultra-low-dropout current regulators, it ♦ 0.2% LED Current Matching maintains the highest possible efficiency over the full ♦ 28mA/LED Drive Capability 1-cell Li+ battery input voltage range. The 1MHz fixed- ♦ frequency switching allows for tiny external compo- Low Input Ripple and EMI nents and the regulation scheme is optimized to ensure ♦ Eliminates Ballast Resistors low EMI and low input ripple. ♦ Logic or PWM Dimming Control An external resistor sets the full-scale LED current, while ♦ Low 0.1µA Shutdown Current two digital inputs control on/off and select amongst three levels of brightness. A pulse-width modulation (PWM) ♦ 2.7V to 5.5V Input Voltage Range signal can also be used to modulate LED brightness, ♦ Soft-Start Limits Inrush Current requiring no additional components. ♦ Output Overvoltage Protection The MAX1573 is available in the tiny chip-scale UCSP™ (4 x 4 grid) and 16-pin thin QFN packages. ♦ Thermal Shutdown Protection ♦ No External Schottky Diode Required ♦ Tiny UCSP (2.1mm x 2.1mm x 0.6mm) and ThinQFN (4mm x 4mm) PackagesApplications Cell Phones, Smart Phones Ordering Information PDAs, Digital Cameras, Camcorders PARTTEMP RANGEPIN-PACKAGE MP3 Players MAX1573EBE-T -40°C to +85°C 14 UCSP (4 x 4) Other Handhelds with Color Displays MAX1573ETE -40°C to +85°C 16 Thin QFN MAX1573ETE+ -40°C to +85°C 16 Thin QFN + Denotes lead-free package. Typical Operating CircuitPin Configurations TOP VIEW 1μF 1μF N.C. GND LED3 LED4 12 11 10 9 C1N C1P C2N C2P VOUT V CIN IN 13 8 LED1 UP TO 4 LEDS 2.7V TO 5.5V IN OUT 1μF 1μF IN 14 7 LED2 MAX1573 ON/OFF MAX1573 C2N 15 6 SET AND EN1 LED1 DIMMING EN2 LED2 CONTROL C1P 16 5 EN2 LED3 1 2 3 4 SET LED4 GND C2P OUT EN1 N.C. RSET THIN QFN4mm × 4mm A "+" SIGN WILL REPLACE THE FIRST PIN INDICATOR ON LEAD-FREE PACKAGES. Pin Configurations continued at end of data sheet. UCSP is a trademark of Maxim Integrated Products, Inc. ________________________________________________________________ Maxim Integrated Products1For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.