DATA SHEET
AAT1274
1.5A Single Flash LED Driver IC
General Description
The AAT1274 is a high-efficiency, 1.5A high-current
boost converter for LED photo flash applications. It
maintains output current regulation by switching the
internal high-side and low-side switch transistors, pulse-
width modulated at a fixed frequency of 2MHz. The high
switching frequency allows the use of a small external
inductor and output capacitor, making the AAT1274 ide-
ally suited in all single cell, Li-ion-powered applications.
Skyworks' proprietary AS
2
Cwire™ (Advanced Simple
Serial Control™) serial digital interface is used to enable,
disable, configure, and program the operation of the
AAT1274. Using the AS
2
Cwire interface, the movie-mode
current level for each LED, and the flash-to-movie-mode
current ratio can be programmed to one of 16 levels. The
AAT1274 includes a separate Flash Enable input to initi-
ate the flash operation and a Flash Inhibit pin which
reduces the flash current to movie-mode levels during
high battery demand.
The maximum flash and movie-mode current is set by
one external resistor where the ratio of flash to movie-
mode current is set at approximately 7.3:1. The AAT1274
can drive one high current LED.
The AAT1274 contains a thermal management system to
protect the device in the event of an output short-circuit
condition. Built-in circuitry prevents excessive inrush
current during start-up. The shutdown feature reduces
quiescent current to less than 1.0μA.
The AAT1274 is available in a Pb-free, thermally-enhanced
TDFN33-14 package and operates over the -40°C to 85°C
temperature range.
Features
•
•
•
•
•
•
•
Input Voltage Range: 2.7V to 5.5V
Single Channel Flash Output
Up to 1.5A Regulated Output Current
Up to 88% Efficiency
2 MHz Switching Frequency
Separate Flash Enable
Single Resistor Sets Flash and Movie Mode Current
▪
AS
2
Cwire Single Wire Programming:
• Movie Mode Current
• Flash/Movie Mode Current Ratio
True Load Disconnect
Soft-Start and Input Current Limit
Over-Voltage (Open LED, Open Circuit), Short Circuit,
and Over-Temperature Protection
-40°C to +85°C Temperature Range
TDFN33-14 Package
•
•
•
•
•
Applications
•
•
•
•
•
LED Photo Flash / Torch
Camera Enabled Mobile Devices
Cellphones/Smartphones
Digital Still Cameras (DSCs)
Multimedia Mobile Phones
Typical Application
L1 1μH
V
BAT
= 2.7V to 5.5V
C
IN
2.2μF
IN
SW
OUT
C
OUT
2.2μF
Flash LED
FL
RSET
R
SET
AAT1274
Enable/Set Input
Flash Enable
Flash Inhibit
EN/SET
FLEN
FLINH
PGND AGND FLGND
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201981A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 21, 2012
1
DATA SHEET
AAT1274
1.5A Single Flash LED Driver IC
Pin Descriptions
Pin #
1,5
2
3
4
6
7
8
9, 12
10
11
13
14
EP
Symbol
AGND
EN/SET
FL
FLEN
IN
PGND
OUT
NC
SW
FLINH
FLGND
RSET
Description
Analog ground pin. Connect AGND to PGND, and FLGND at a single point as close to the AAT1274 as possible.
Enable and Serial Control input. EN/SET is the AS2Cwire addressing and programming input to: a) adjust the
movie-mode current level; b) select the Flash-to-Movie-mode ratio;
LED Flash current sink pin. Connect the cathode of Flash LED to FL.
Flash enable pin. A low-to-high transition on the FLEN pin initiates a
fl
ash pulse and a high-to-low transition
on the FLEN pin terminates a
fl
ash pulse
Flash output boost converter power input. Connect IN to the input power source. Connect a 2.2μF or larger
ceramic capacitor from IN to PGND and locate as close as possible to the AAT1274 package for optimum per-
formance.
Power ground. Connect PGND to the same single point as AGND located as close to the AAT1274 as possible
Power output of the boost converter. Connect a 2.2μF or larger ceramic capacitor from OUT to PGND as close
as possible to the AAT1274. Connect OUT to the anode of the Flash LED.
Not connected
Boost converter switching node. Connect a 1μH inductor between SW and IN.
Flash inhibit pin. FLINH is an active HIGH control input with an internal 200kΩ resistor to AGND. A low-to-
high transition on the FLINH pin reduces FL sink current to the maximum (default) movie-mode current level.
Flash ground pin. Connect FLGND to PGND, and AGND at a single point as close to the AAT1274 as possible.
Flash current set pin. Connect a resistor from RSET to AGND to program the desired
fl
ash current for the cur-
rent sink FL.
Electrical back contact. Connect to a good thermal ground pad
Pin Configuration
TDFN33-14
(Top View)
AGND
EN/SET
FL
FLEN
AGND
IN
PGND
1
2
3
4
5
6
7
14
13
12
11
10
9
8
RSET
FLGND
N/C
FLINH
SW
N/C
OUT
2
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201981A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 21, 2012
DATA SHEET
AAT1274
1.5A Single Flash LED Driver IC
Absolute Maximum Ratings
1
T
A
= 25°C unless otherwise noted.
Symbol
IN, OUT, SW
EN/SET, FLEN,
FLINH, RSET, FL
T
J
T
S
T
LEAD
Description
Maximum Rating
Maximum Rating
Operating Junction Temperature Range
Storage Temperature Range
Maximum Soldering Temperature (at Leads, 10 sec)
Value
-0.3 to 6.0
-0.3 to V
IN
+ 0.3
-40 to 150
-65 to 150
300
Units
V
C
Thermal Information
2
Symbol
JA
P
D
Description
Thermal Resistance
3
Maximum Power Dissipation
Value
50
2
Units
O
C/W
W
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions
specified is not implied.
2. Mounted on an FR4 board.
3. Derate 20mW/°C above 25°C.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201981A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 21, 2012
3
DATA SHEET
AAT1274
1.5A Single Flash LED Driver IC
Electrical Characteristics
V
IN
= 3.6V; C
IN
= C
OUT
= 2.2μF; R
SET
= 107kΩ; L = 1μH. T
A
= -40
o
C to 85°C unless otherwise noted. Typical values are
at T
A
= 25°C.
Symbol
Description
Conditions
Min
2.7
EN/SET = FLEN = IN, Set FL Load = 1.5A
EN/SET = IN, FLEN = AGND
EN/SET, FLEN, = AGND
R
SET
= 107kΩ
R
SET
= 107kΩ = 1.2A
R
SET
= 107kΩ, Movie mode current set to 100%
T
A
= 25°C
0.67
0.23
1.2
1.5
±10
206
2.0
140
15
Typ
Max
5.5
5.5
1
1.0
Units
V
V
mA
μA
A
%
mA
MHz
°C
°C
V
Power Supply – Switching Flash Driver
Input Voltage Range
V
IN
V
OUT(MAX)
Maximum Output Voltage
I
IN(Q)
Supply Current
I
SHDN(MAX)
Input Shutdown Current
Output Current, Flash Mode
I
FL
I
FL(ACC)
Flash Current Accuracy
I
MM(LOAD)
Total Output Current, Movie Mode
F
OSC
Switching Frequency
T
SD
Over-Temperature Shutdown Threshold
T
SD(HYS)
Over-Temperature Shutdown Hysteresis
EN/SET, FLEN
V
EN/SET(H)
,
EN/SET, FLEN Input High Threshold
V
FLEN(H)
V
EN/SET(L)
,
EN/SET, FLEN Input Low Threshold
V
FLEN(L)
I
EN/SET,
I
FLEN
EN/SET, FLEN Input Leakage Current
V
T(FLINH)
FLINH Input Threshold Voltage
R
IN(FLINH)
FLINH Input Resistance to AGND
t
EN/SET(LO)
EN/SET Serial Interface Low Time
t
EN/SET(HI-MIN)
Minimum EN/SET High Time
t
EN/SET(HI-MAX)
Maximum EN/SET High Time
t
EN/SET(OFF)
EN/SET Off timeout time
EN/SET Latch Timeout Time
t
ENSET(LAT)
t
FLEN(ON)
FLEN On Delay Time
t
FLEN(OFF)
FLEN Off Delay Time
t
FLINH_ON
FLINH ON Delay Tim
e
1.5
2.5
1.4
0.4
V
EN/SET
, V
FLEN
= IN = 5V
-1
½
IN
200
0.3
50
75
500
500
EN/SET = AGND
EN/SET = AGND
40
10
93
75
1
V
μA
V
kΩ
μs
ns
μs
μs
μs
μs
μs
μs
4
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201981A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 21, 2012
DATA SHEET
AAT1274
1.5A Single Flash LED Driver IC
Typical Characteristics
Flash Mode Efficiency vs. Input Voltage
100
90
90
320mA, V
F
= 2.91V
540mA, V
F
= 3.00V
700mA, V
F
= 3.04V
900mA, V
F
= 3.04V
1500mA, V
F
= 3.15V
1200mA, V
F
= 3.27V
Movie Mode Efficiency vs. Input Voltage
204mA
104mA
52mA
85
Efficiency (%)
80
70
60
50
40
2.7
Efficiency (%)
5.5
80
75
70
65
60
55
3.1
3.5
3.9
4.3
4.7
5.1
50
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
Input Voltage (V)
Boost Switching Frequency vs. Input Voltage
(Movie Mode; L = 1µH)
Switching Frequency (MHz)
3
2.5
2
1.5
1
0.5
0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
0.03
Shutdown Current vs. Input Voltage
(V
EN/SET
= V
FLEN
= 0V)
Shutdown Current (µA)
0.025
0.02
0.015
0.01
0.005
0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
85°C
25°C
-40°C
25°C
-40°C
5.5
Input Voltage (V)
Input Voltage (V)
Supply Current vs. Input Voltage
(V
EN
= V
FLEN
= 3.6V)
1000
800
700
600
500
400
300
200
100
0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Movie Mode LED Current vs. Temperature
(I
FL
= 206mA/Ch; V
IN
= 3.6V; L = 1µH)
225
220
215
210
205
200
195
190
185
-40
-15
10
35
60
85
85°C
25°C
-40°C
Input Voltage (V)
Output Current (mA)
900
Supply Current (µA)
Temperature (°C)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201981A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 21, 2012
5
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