PRODUCT DATASHEET
AAT2848
ChargePump
TM
High-Current Charge Pump For Backlight Display and Flash Applications
Features
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Tri-Mode (1x/1.5x/2x) Charge Pump
Four 30mA Backlight LED Channels
Independent S
2
Cwire Control for Backlight
32-Level Programmable Backlight Current Control—
Linear, Inverting
Two 300mA Flash LED Channels
Independent S
2
Cwire Control for Flash
16-Level Programmable Flash Current Control—
Linear, Inverting
User-Programmable Full Scale Current for Backlight
and Flash
User-Programmable Fade-In/Fade-Out Function for
Backlight
User-Programmable Safety Timer for Flash LED
Protection
Built-In Thermal Protection
Automatic Soft-Start
-40°C to +85°C Temperature Range
Available in TQFN33-20 Package
General Description
The AAT2848 is a tri-mode charge pump optimized for
systems operating with lithium-ion/polymer batteries. The
charge pump provides power for both white LED backlight
and flash, with an integrated four channel backlight LED
current sink plus two channel flash LED current sinks.
Each backlight channel can drive up to 30mA, while each
flash current sink/channel can drive up to 300mA (600mA
total). Two independent S
2
Cwire™ (AnalogicTech’s Simple
Serial Control™) serial digital interface inputs enable,
disable, and set LED current to one of 32 levels for the
backlight and to one of 16 levels for the flash, with full-
scale current independently set for backlight and flash
using external resistors.
The AAT2848 offers a built-in fade-in/out function for
linear control of the backlight current during ON/OFF
transitions. The fade time is programmable by an exter-
nal capacitor.
The AAT2848 also offers a built-in flash timeout function
as a safety feature associated with the high power flash
driver. The safety timer is also programmable via an
external capacitor.
The AAT2848 is equipped with built-in short-circuit and
over-temperature protection. The soft-start circuitry pre-
vents excessive inrush current at start-up and mode
transitions. The AAT2848 is available in a Pb-free, space
saving TQFN33-20 package and operates over the -40°C
to +85°C ambient temperature range.
Applications
• Camera Enabled Mobile Devices
• Digital Still Cameras
• Multimedia Mobile Phones
Typical Application
C1
1μF
C2
1μF
C2+
OUT
C
OUT
2.2μF
Flash LEDs
Lumileds PWF1
or equivalent
WLEDs
OSRAM LW M673
or equivalent
C1- C1+ C2-
IN
V
BAT
C
IN
4.7μF
AAT2848
BL1
BL2
BL3
BL4
FL1
FL2
S
2
Cwire
Backlight Control
S
2
Cwire
Flash Control
BENS
FENS
BSET
FSET
R
BSET
15k
R
FSET
14.3k
FLTMR
C
FLTMR
330nF
FADE
C
FADE
47nF
AGND
PGND
2848.2008.05.1.0
www.analogictech.com
1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
