Datasheet

1.0 A LED Flash Driver with
I
2
C-Compatible Interface
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
I
2
C programmable
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
F
, die/LED temperature readback
Control
I
2
C-compatible control registers
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
inductive boost converter, an I
2
C-compatible interface, and a
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
LED current for all LED V
F
and battery voltage conditions.
Two independent TxMASK inputs permit the flash LED current
and battery current to reduce quickly during a power amplifier
current burst. The I
2
C-compatible interface enables the pro-
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
L
ED_OUT
EN SGND
SCL
SDA
TxMASK1/TORCH
TxMASK2/ILED/ADC
GPIO1
GPIO2
MAX 1.0A
VIN
10779-001
DIGITAL
INPUT/
OUTPUT
Li-ION +
Li-ION +
PGND
C1
L1
INDUCTOR
LED
ANODE
C2
AREA = 16.4mm
2
10779-002

Summary of content (28 pages)