A8440 LED DRIVER Datasheet

A8440 Datasheet, PDF, Equivalent


Part Number

A8440

Description

4-CHANNEL WHITE LED DRIVER

Manufacture

AiT Semiconductor

Total Page 16 Pages
Datasheet
Download A8440 Datasheet


A8440
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-

A8440
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+
C1-
C2-
C2+
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 Cathode Terminal
LED3 Cathode Terminal
LED2 Cathode Terminal
LED1 Cathode Terminal
REV1.2 - JAN 2007 RELEASED – JUL 2008 REVISED -
-2-


Features AiT Semiconductor Inc. www.ait-ic.com A 8440 4CHANNEL WHITE LED DRIVER 1x /1.5x CHARGE PUMP DISPLAY BACKLIGHT SOLUTION DESCRIPTION FEATURES The A8440 is a complete backlight display solution th at 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 re gulated current sources ensure excellen t LED current and brightness matching. LED driver current is programmed by an external resistor. The A8440 operates o ver an input voltage range from 3V to 5 .5V, optimized for WLED applications po wered by Li-Ion battery, requiring only for low cost ceramic capacitors. The A 8440 provides excellent efficiency by o perating the charge pump in a gain of 1 or 1.5. Maximum efficiency is achieved over Li-Ion battery voltage range by s electing the proper gain based on the L ED forward voltage requirements. Indiv idually Current Regulation for Up to 4 LEDs Input Voltage Range: 2.7Vto 5.5V Wide Current Range, up to.
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