AAT1282 Datasheet, PDF (2/22 Pages) Skyworks Solutions Inc. – 2A Driver for High Intensity LED Camera Flash

DATA SHEET
AAT1282
2A Driver for High Intensity LED Camera Flash
Typical Application Circuit
L1
1μH
VBAT
CIN
2.2μF
Flash
Enable
Enable
I²C
SDA
Interface
SCL
RSET
80.6kΩ
IN
SW
OUT
AAT1282
FLEN
FLOUTA
EN
FLOUTB
SDA
CT
SCL
RSET AGND PGND FLGND
Flash LEDs
COUT
2.2μF
CT
47nF
Super Capacitor
RSCB1
30kΩ
RSCB2
30kΩ
Pin Descriptions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Symbol
CT
EN
FLEN
AGND
IN
SW
PGND
OUT
SCL
SDA
FLOUTB
FLGND
FLOUTA
RSET
EP
Function
I
I
I
P
PI
O
P
O
I
I
O
P
O
I
Description
Flash timer control input. Connect a capacitor between CT and AGND to set default ON time for
the flash output. A 47nF ceramic capacitor defaults the flash timer to 600ms. Alternative timeout
periods can be programmed via I²C. To disable the flash timer, connect CT to AGND.
Enable control input, an active HIGH asserted input. EN must be strobed low-to-high to enable
the AAT1282 to accept I²C programming instructions.
Flash enable pin. A low-to-high transition on the FLEN pin initiates a flash pulse and starts the
flash timer.
Analog ground pin. Connect AGND to PGND and FLGND at a single point as close to the AAT1282
as possible.
Power input. Connect IN to the input power supply voltage. Connect a 2.2μF or larger ceramic
capacitor from IN to PGND as close as possible to the AAT1282.
Step-up converter switching node. Connect a 1μH inductor between SW and IN.
Power ground pin. Connect PGND to AGND and FLGND at a single point as close to the AAT1282
as possible.
Power output of the step-up converter. Connect a 2.2μF or larger ceramic capacitor from OUT to
PGND as close as possible to the AAT1282. Connect OUT to the super capacitor and the anode(s)
of the Flash LED(s).
I²C Interface: Serial Control Line.
I²C Interface: Serial Data/Address.
Flash Output B. Connect cathode of Flash LEDB to FLOUTB. For a single flash LED, connect
FLOUTB and FLOUTA together. For two flash LEDs, each output will conduct 50% of the total flash
output current. Can be turned off or on via I²C.
Flash ground pin. Connect FLGND to PGND and AGND at a single point as close to the AAT1282
as possible.
Flash Output A. Connect cathode of Flash LED A to FLOUTA. For a single flash LED, connect
FLOUTA and FLOUTB together. For two flash LEDs, each output will conduct 50% of the total flash
output current. Can be turned off or on via I²C.
Flash current setting input. A 80.6kΩ resistor from RSET to AGND sets the maximum flash cur-
rent available at FLOUTA and FLOUTB to 2000mA. Each FLOUTA and FLOUTB channel will con-
duct 50% of the maximum programmed current (1000mA). The AAT1282’s flash-to-movie-mode
default ratio is a fixed at 7.3 but can be adjusted via I²C.
Exposed paddle (bottom); Connect EP to PGND as close as possible to the AAT1282.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
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202305C • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013