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A8440 Dataheets PDF



Part Number A8440
Manufacturers AiT Semiconductor
Logo AiT Semiconductor
Description 4-CHANNEL WHITE LED DRIVER
Datasheet A8440 DatasheetA8440 Datasheet (PDF)

AiT Semiconductor Inc. www.ait-ic.com A8440 4CHANNEL WHITE LED DRIVER 1x /1.5x CHARGE PUMP DISPLAY BACKLIGHT SOLUTION DESCRIPTION FEATURES The A8440 is a complete 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 30mA 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 op.

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AiT Semiconductor Inc. www.ait-ic.com A8440 4CHANNEL WHITE LED DRIVER 1x /1.5x CHARGE PUMP DISPLAY BACKLIGHT SOLUTION DESCRIPTION FEATURES The A8440 is a complete 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 30mA 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 30mA 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 120mA (4 x 30mA) Peak Efficiency : 90% Fixed Frequency 1MHz Power-Saving Shutdown mode of 1uA 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 1uA of supply current when shutdown. The A8440 LED dimming can be accomplished 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 A8440TQ16VR QFN16 (4x4mm) Q16 A8440Q16R A8440Q16VR Note R: Tape & Reel V: Green Package AiT provides all Pb free products Suffix “ V “ means Green Package REV1.2 - JAN 2007 RELEASED – JUL 2008 REVISED - -1- AiT Semiconductor Inc. www.ait-ic.com A8440 4CHANNEL WHITE LED DRIVER 1x /1.5x CHARGE PUMP DISPLAY BACKLIGHT SOLUTION PIN DESCRIPTION Pin # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Top View Top View Pin Name Function EN CTR0 CTR1 CTR2 RSET VOUT VIN C1+ C1C2C2+ GND LED4 LED3 LED2 LED1 Enable Input Active High Digital Control Input 0 Digital Control Input 1 Digital Control Input 2 Set LED Output Current by the Current Sourced out of the RSET pin Output Pin, Charge Pump output connected to the LED anodes Input Pin, Supply Voltage Bucket Capacitor 1 Terminal Bucket Capacitor 1 Terminal Bucket Capacitor 2 Terminal Bucket Capacitor 2 Terminal Ground Pin LED4 Cath.


MSZ5272B A8440 A4732


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