A8440 Datasheet | AiT Semiconductor

DESCRIPTION FEATURES The A8440 is a plete backlight display solution that is designed to independently control LEDs. The A8440 is a charge pump WLED driver capable of driving up to 4 LEDs with 30m A each LED. Its four tightly regulated current sources ensure excellent LED current and brightness matching. LED driver current is programmed by an external resistor. The A8440 operates over an input voltage range from 3V to 5.5V, optimized for WLED applications powered by Li-Ion battery, requiring only for low cost ceramic capacitors. The A8440 provides excellent efficiency by operating the charge pump in a gain of 1 or 1.5. Maximum efficiency is achieved over Li-Ion battery voltage range by selecting the proper gain based on the LED forward voltage requirements. Individually Current Regulation for Up to 4 LEDs Input Voltage Range: 2.7Vto 5.5V Wide Current Range, up to 30m A per LED 3-bit Digital Output Control 3% Maximum Tolerance Current Matching 1x and 1.5x mode Operating with Automatic Switchover High Available Total LED Current 120m A (4 x 30m A) Peak Efficiency : 90% Fixed Frequency 1MHz Power-Saving Shutdown mode of 1u A Open LED Protection Soft-Start Over-Current-Protection and Current Limiting Available in TQFN-16 (3x3mm) and QFN16 (4x4mm) Package The A8440 has a fixed 1MHz switching frequency, consuming less than 1u A of supply current when shutdown. The A8440 LED dimming can be acplished by several methods including using a DC voltage to set the RSET pin current, applying a PW signal on the control signals, or adding a switched resistor in parallel with RSET. The enable input pin allows the A8440 to be placed in power-down mode. The A8440 is available in 16pin TQFN (3x3mm) QFN16 (4x4mm) package. APPLICATION Portable Devices, Mobile Phone, DVR, Smart Phone...etc. Hand-held Devices, PDA, PMP, MP3, DSC...etc. White LED Backlight Application LED Modules Typical Application ORDERING INFORMATION Package Type Part Number TQFN16(3x3mm) TQ16 A8440TQ16R...