A8434EESTR-T

A8434EESTR-T Datasheet

A8434 6-Channel High Efficiency Charge Pump White LED Driver

Part	Datasheet
A8434EESTR-T	A8434EESTR-T (pdf)

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A8434 6-Channel High Efficiency Charge Pump White LED Driver Proprietary adaptive control scheme 1x, 2x typical WLED current matching Drives up to 6 white LEDs Main display backlight up to 6 WLEDs Main display and sub display backlight Main display and low-current flash/torch 30 mA per WLED 2x serial dimming interfaces 320 mA charge pump capability Low EMI design and soft start function Short circuit, overvoltage, thermal shutdown protection mm nominal height very thin profile , 3 x 3 mm footprint packages Package 16 pin QFN/MLP suffix ES Approximate scale 1:1 The A8434 high efficiency charge pump ICs offer a simple, low-cost WLED white LED driver solution for driving up to six WLEDs in various application configurations, either all six backlighting a single display, or for multiple displays, such as four WLEDs as the main display backlight, with the other two WLEDs used for backlighting a sub display or a low-current flash/torch. Using a proprietary control scheme 1x, and 2x , the A8434 can deliver well-matched WLED current while maintaining the highest efficiency and low EMI. The WLED current is regulated over the entire range of Li+ battery voltage to provide uniform intensity. WLED brightness and on/off can be controlled for the main display and sub display/torch through 2 single-wire serial interface pins. The A8434 is available in an QFN/MLP-16 space-conserving 3 x 3 mm footprint ES package. Applications include: White LED backlights for cellular phones, PDAs Digital cameras, camcorders Portable audio devices and MP3s Other portable device white LED backlighting VBATT CIN 1 µF C1 1 µF C1+ VOUT D1 LED1 C2 1 µF LED2 C2+ A8434 D2 D3 LED3 RSET ISET LED4 LED5 On/Off and Dimming ENS GND LED6 Control Figure x 30 mA WLED display COUT 1 µF VBATT to V CIN 1 µF C1 1 µF C2 1 µF RSET On/Off and Dimming Control VOUT LED1 LED2 C2+ A8434 LED3 ISET LED4 Use the following complete part number when ordering: Packaging* Package Type A8434EESTR-T 7-in. reel, 1500 pieces/reel ES, 3 x 3 mm MLP-16 *Contact Allegro for additional packing options. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 508 853-5000 A8434 6-Channel High Efficiency Charge Pump White LED Driver Pin-out Diagram ES Package 16 C1+ 15 14 VIN 13 C2+ 1 VOUT 2 ISET 3 ENS 4 12 GND 11 LED1 EP 10 LED2 9 LED3 ENM 5 LED6 6 LED5 7 LED4 8 Top View Terminal List Table Name C1+ C2+ ENS ENM EP GND ISET LED1, LED2, LED3, and LED4 LED5 and LED6 VOUT Number 13 16 15 1 4 5 12 8, 9, 10, and 11 6 and 7 Function Negative terminal of capacitor C1. Connect capacitor C1 between C1+ and Positive terminal of capacitor C1. Negative terminal of capacitor C2 Positive terminal of capacitor C2. Connect capacitor C2 between C2+ and Enable and dimming control input for sub display WLED group. Enable and dimming control input for main display WLED group. Exposed metal pad on bottom side. Connect this to ground plane for better thermal performance. Ground. Connect RSET resistor to ground to set desired constant current through main and sub WLEDs. ILED max = 220 x V / RSET Current sink for main display WLEDs. If not used, connect to VOUT, but do not leave open. If left open, the IC works in 2 x mode. Current sink for sub display WLEDs. If not used, connect to VOUT, but do not leave open. If left open, the IC works in 2 x mode. Power supply voltage input. Charge pump output voltage for display backlight and flash/torch LED anodes. Connect a 1 uF capacitor, COUT, between VOUT and GND see figure Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 508 853-5000 A8434 6-Channel High Efficiency Charge Pump White LED Driver ELECTRICAL CHARACTERISTICSa VIN = ENM = ENS = V, C1 = C2 = 1 uF, CIN = COUT = 1 uF, RSET = kΩ, TA = to +85°C typical values are at TA = 25°C unless otherwise noted Characteristics

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A8434 6-Channel High Efficiency Charge Pump White LED Driver

Proprietary adaptive control scheme 1x, 2x typical WLED current matching Drives up to 6 white LEDs

Main display backlight up to 6 WLEDs Main display and sub display backlight Main display and low-current flash/torch 30 mA per WLED 2x serial dimming interfaces 320 mA charge pump capability Low EMI design and soft start function Short circuit, overvoltage, thermal shutdown protection mm nominal height very thin profile , 3 x 3 mm footprint packages

Package 16 pin QFN/MLP suffix ES

Approximate scale 1:1

The A8434 high efficiency charge pump ICs offer a simple, low-cost WLED white LED driver solution for driving up to six WLEDs in various application configurations, either all six backlighting a single display, or for multiple displays, such as four WLEDs as the main display backlight, with the other two WLEDs used for backlighting a sub display or a low-current flash/torch. Using a proprietary control scheme 1x, and 2x , the A8434 can deliver well-matched WLED current while maintaining the highest efficiency and low EMI.

The WLED current is regulated over the entire range of Li+ battery voltage to provide uniform intensity. WLED brightness and on/off can be controlled for the main display and sub display/torch through 2 single-wire serial interface pins.

The A8434 is available in an QFN/MLP-16 space-conserving 3 x 3 mm footprint ES package.

Applications include:

White LED backlights for cellular phones, PDAs Digital cameras, camcorders Portable audio devices and MP3s Other portable device white LED backlighting

VBATT

CIN 1 µF

C1 1 µF C1+

VOUT D1

LED1

C2 1 µF

LED2

C2+ A8434

D2 D3

LED3

RSET

ISET

LED4

LED5

On/Off and Dimming

ENS GND LED6

Control

Figure x 30 mA WLED display

COUT 1 µF

VBATT to V

CIN 1 µF

C1 1 µF

C2 1 µF

RSET

On/Off and Dimming Control

VOUT

LED1

LED2

C2+ A8434 LED3

ISET

LED4
Use the following complete part number when ordering:

Packaging*

Package Type

A8434EESTR-T
7-in. reel, 1500 pieces/reel

ES, 3 x 3 mm MLP-16
*Contact Allegro for additional packing options.

Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 508 853-5000

A8434
6-Channel High Efficiency Charge Pump White LED Driver

Pin-out Diagram

ES Package
16 C1+ 15 14 VIN 13

C2+ 1 VOUT 2

ISET 3 ENS 4
12 GND
11 LED1 EP
10 LED2
9 LED3

ENM 5 LED6 6 LED5 7 LED4 8

Top View

Terminal List Table

Name C1+ C2+ ENS ENM EP GND

ISET

LED1, LED2, LED3, and LED4

LED5 and LED6

VOUT

Number 13 16 15 1 4 5 12
8, 9, 10, and 11
6 and 7

Function Negative terminal of capacitor C1. Connect capacitor C1 between C1+ and Positive terminal of capacitor C1. Negative terminal of capacitor C2 Positive terminal of capacitor C2. Connect capacitor C2 between C2+ and Enable and dimming control input for sub display WLED group. Enable and dimming control input for main display WLED group. Exposed metal pad on bottom side. Connect this to ground plane for better thermal performance. Ground. Connect RSET resistor to ground to set desired constant current through main and sub WLEDs. ILED max = 220 x V / RSET Current sink for main display WLEDs. If not used, connect to VOUT, but do not leave open. If left open, the IC works in 2 x mode. Current sink for sub display WLEDs. If not used, connect to VOUT, but do not leave open. If left open, the IC works in 2 x mode. Power supply voltage input. Charge pump output voltage for display backlight and flash/torch LED anodes. Connect a 1 uF capacitor, COUT, between VOUT and GND see figure

Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 508 853-5000

A8434
6-Channel High Efficiency Charge Pump White LED Driver

ELECTRICAL CHARACTERISTICSa VIN = ENM = ENS = V, C1 = C2 = 1 uF, CIN = COUT = 1 uF, RSET = kΩ,

TA = to +85°C typical values are at TA = 25°C unless otherwise noted

Characteristics

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Datasheet ID: A8434EESTR-T 516075