1.0 A LED Flash Driver with

Data Sheet

ADP1649

Rev. 0

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FEATURES

Ultracompact solution

Small, 2 mm × 1.5 mm, 12-ball WLCSP package

Smallest footprint, 1 mm height, 1 μH power inductor

LED current source for local LED grounding

Simplified routing to and from the LED

Improved LED thermals

Synchronous 3 MHz PWM boost converter, no external diode

High efficiency: 90% peak

Reduces high levels of input battery current during flash

Limits battery current drain in torch mode

Currents of up to 1000 mA in flash mode for 1 LED with

±7% accuracy over all conditions

Currents of up to 200 mA in torch mode

Programmable dc battery current limit (4 settings)

Programmable flash timer up to 1600 ms

Low VBAT mode to reduce LED current automatically

4-bit ADC for LED V

Control

External strobe and torch input pins

2 transmitter mask (TxMASK) inputs

Safety

Thermal overload protection

Inductor fault detection

LED short-circuit and open-circuit protection

APPLICATIONS

Camera enabled cellular phones and smart phones

Digital still cameras, camcorders, and PDAs

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

Figure 2. PCB Layout (WLCSP)

GENERAL DESCRIPTION

The ADP1649 is a very compact, highly efficient, single white

LED flash driver for high resolution camera phones that improves

picture and video quality in low light environments. The device

integrates a programmable 1.5 MHz or 3 MHz synchronous

1000 mA current source. The high switching frequency enables

the use of a tiny, 1 mm high, low cost, 1 µH power inductor, and

the current source permits LED cathode grounding for thermally

enhanced, low EMI, and compact layouts.

The LED driver maximizes efficiency over the entire battery

voltage range to maximize the input power-to-LED power

conversion and to minimize battery current draw during flash

events. A programmable dc battery current limit safely maximizes

Two independent TxMASK inputs permit the flash LED current

and battery current to reduce quickly during a power amplifier

grammability of timers, currents, and status bit readback for

monitoring the operation and for safety control.

The ADP1649 is available in a compact 12-ball, 0.5 mm pitch

WLCSP package, and operates within specification over the full

−40°C to +125°C junction temperature range.

ADP1649

10µF

1.0µH

INPUT VOLTAGE = 2.7V TO 5.0V

VOUT

PGND

SW

STROBE

10µF

LED_OUT

EN

SGND

SCL

SDA

TxMASK1/TORCH

TxMASK2/ILED/ADC

GPIO1

GPIO2

MAX 1.0A

VIN

DIGITAL

INPUT/

OUTPUT

Li-ION +

Li-ION +

PGND

C1

L1

INDUCTOR

LED

ANODE

C2