202111A.pdf

DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
General Description
Features
The AAT1236 is a highly integrated, high efficiency power
solution for white LED and keypad backlights in mobile/
portable devices. It is based on a switching boost converter which steps up the single cell lithium-ion/polymer
battery voltage to drive 5 strings of series-connected
white LEDs with precision current regulation. The AAT1236
is capable of driving a total of four LEDs per channel.
• Input Supply Voltage Range: 2.7V to 5.5V
• Maximum Boost Output Drive: Up to 24V at 100mA
• Up to 85% Efficient Operation
• Up to 2MHz Switching Frequency with Small Inductor
• User-Programmable Full-Scale LED Current, Up to
30mA
• Two-Wire, I2C Compliant Serial Interface
▪ Two Addressable Registers
• Independent LED Current Control by Group
▪ Backlight Group B1-B2, 16 Settings
▪ Auxiliary Group A1-A3, 16 Settings
• Independent LED ON/OFF Control
▪ Fast, 400kHz Serial Transfer Rate
• Non-Pulsating, High-Performance LED Current Drive
for Uniform Illumination
▪ 10% Absolute Accuracy
▪ 2% Channel-to-Channel Matching
• Over-Voltage and Over-Temperature Protection
• Automatic Soft-Start Minimizes Large Inrush Current
at Startup
• Available in 3x4mm TDFN34-16 Package
The boost converter can produce an output drive of up
to 24V at 100mA. The high switching frequency (up to
2MHz) provides fast response to load transients and
allows the use of small external components. A fully
integrated control circuit simplifies the design and reduces total solution size.
A two-wire I2C serial digital interface is used to individually turn each output sink on/off and adjust the LED current by group. Unlike conventional pulse width modulation (PWM) control of LED brightness, the AAT1236 drives
the LEDs with constant, non-pulsating current. The interface is fully compliant to the Fast/Standard mode I2C
specification, allowing a transfer rate of up to 400kHz.
A similar device is also available with a proprietary
Advanced Simple Serial Control™ (AS2Cwire™) single
wire interface; please see the AAT1235 datasheet.
Applications
• Digital Still Cameras (DSCs)
• Keypad Backlight
• Large Panel Displays
• Mobile Handsets
• PDAs and Notebook PCs
• Personal Media Players
• White LED Backlight
The AAT1236 is available in a Pb-free, thermally-enhanced
16-pin 3x4mm TDFN package and is specified for operation over the -40°C to +85°C temperature range.
Typical Application
L=2.2µH
D1
Keypad or
RGB LEDs
Up to 24V max
C OUT
2.2µF
R2
187kΩ
Backlight
LEDs
LIN
Input :
2.7V~5.5V
VIN
CIN
2.2µF
IN
Enable
I 2C
Interface
B1
SW
B2
A1
RSET
A3
OV
AAT1236
EN SDA SCL
A2
GND
AGND
R3
12.1kΩ
R1
22.6kΩ
SDA
SCL
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
1
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Pin Descriptions
Pin #
Symbol
1
VIN
2
OV
3
4
5
EN
B1
B2
6
RSET
7
IN
8
GND
9
SW
10
11
12
13
14
15
16
EP
SDA
SCL
AGND
A3
A2
A1
LIN
Function
Input supply for the converter. Connect a 2.2µF or larger ceramic capacitor from VIN to GND.
Boost output over voltage detect pin. Use resistor divider to set the circuit’s external over-voltage protection. See Applications Information for details.
Enable pin.
Backlight current sink 1. Connect the cathode of the last LED in the string to B1.
Backlight current sink 2. Connect the cathode of the last LED in the string to B2.
LED current set resistor. A 22.6kW resistor from RSET to AGND sets the maximum LED current in A1-A3
and B1-B2 to 20mA.
Input bias supply for the internal circuitry. Connect IN to VIN directly at the AAT1236.
Power ground for the boost converter. Connect GND to AGND at a single point as close to the AAT1236 as
practical.
Boost converter switching node. A 2.2µH inductor, connected between SW and LIN, sets the boost converter's switching frequency.
I2C interface serial data line.
I2C interface serial clock line.
Ground pin. Connect AGND to GND at a single point as close to the AAT1236 as practical.
Auxiliary current sink 3. Connect the cathode of the last LED in the string to A3.
Auxiliary current sink 2. Connect the cathode of the last LED in the string to A2.
Auxiliary current sink 1. Connect the cathode of the last LED in the string to A1.
Switched power input. Connect LIN to the external power inductor.
Exposed paddle (bottom). Connected internally to SW. Connect to SW or leave floating.
Pin Configuration
TDFN34-16
(Top View)
VIN
OV
EN
B1
B2
RSET
IN
GND
2
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
LIN
A1
A2
A3
AGND
SCL
SDA
SW
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Absolute Maximum Ratings1
TA = 25°C unless otherwise noted.
Symbol
Description
Value
Units
VIN, IN
SW
EN, SCL, SDA, Bx,
Ax, RSET, OV, LIN
TS
TJ
TLEAD
Input Voltage
Switching Node
-0.3 to 6.0
28
V
V
VIN + 0.3
V
-65 to 150
-40 to 150
300
°C
°C
°C
Value
Units
50
2
°C/W
W
Maximum Rating
Storage Temperature Range
Operating Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Thermal Information2
Symbol
qJA
PD
Description
Thermal Resistance
Maximum Power Dissipation3
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. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on an FR4 circuit board.
3. Derate 20mW°C above 40°C ambient temperature.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
3
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Electrical Characteristics1
VIN = 3.6V; CIN = 2.2µF;TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.
Symbol
Description
Conditions
Power Supply
VIN
Input Voltage Range
VOUT(MAX)
Maximum Output Voltage
VUVLO
ICC
ISHDN(MAX)
IOX
IDX
IDX-Matching
VOV
RDS(ON)N
RDS(ON)IN
TSS
UVLO Threshold
Operating Current (No Switching)
VIN Pin Shutdown Current
Maximum Continuous Output Current
Current Sink Accuracy
Current Matching Between Any Sink
Channels
OVP Threshold Voltage
OVP Threshold Hysteresis
Low Side Switch On Resistance
Input Disconnect Switch
Soft-Start Time
ISET
Current Set Ratio
ILIMIT
Input Switch Current Limit
Enable Input – EN
VEN(L)
Enable Threshold Low
VEN(H)
Enable Threshold High
I2C Serial Interface – SCL, SDA
FSCL
Clock Frequency
TLOW
Clock Low Period
THIGH
Clock High Period
THD_STA
Hold Time START Condition
TSU_STA
Setup Time for Repeat START
TSU_DAT
Data Setup Time
THD_DAT
Data Hold Low
TSU_STO
Setup Time for STOP Condition
Bus Free Time Between STOP and
TBUF
START Condition
VIL
Input Threshold Low
VIH
Input Threshold High
II
Input Current
VOL
Output Logic Low (SDA)
Thermal Protection
TJ-TH
TJ Thermal Shutdown Threshold
TJ-HYS
TJ Thermal Shutdown Hysteresis
Min
Typ
2.7
VIN Rising
Hysteresis
VIN Falling
B1 = B2 = A1 = A2 = A3 = 1.2V,
2mA Setting, RSET = 226kW
EN = GND
VO = 24V
RSET = 22.6kW
RSET = 22.6kW, A1 = A2 = A3 = B1 =
B2 = 0.4V
VOUT Rising
Max
Units
5.5
24
2.7
V
V
V
mV
V
300
µA
1.0
150
1.8
100
18
1.1
IOUT = 100mA
IOUT = 100mA
From Enable to Output Regulation;
VFB = 300mV
ISINK/IRSET, VRSET = 0.6V
20
22
µA
mA
mA
2
5
%
1.2
100
80
200
1.3
V
mV
mW
mW
300
µs
760
A/A
A
1.2
0.4
V
V
400
kHz
µs
µs
µs
µs
ns
µs
µs
1.4
1.3
0.6
0.6
0.6
100
0
0.6
0.9
1.3
2.7 ≤ VIN ≤ 5.5
2.7 ≤ VIN ≤ 5.5
µs
0.4
1.4
-1.0
1.0
0.4
IPULLUP = 3mA
140
15
V
V
µA
V
°C
°C
1. The AAT1236 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls.
4
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
I2C Interface Timing Details
SDA
TSU_DAT
TLOW
THD_STA
TBUF
SCL
THD_STA
THD_DAT
THIGH
TSU_STA
TSU_STO
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
5
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Typical Characteristics
Efficiency vs. LED Current
Efficiency vs. LED Current
(Group B On; Group A Off)
(Group B Off; Group A On)
83
84
VIN = 5V
81
80
VIN = 3.6V
79
VIN = 4.2V
78
77
82
81
VIN = 3.6V
80
79
VIN = 4.2V
78
76
77
1.6
3.9
6.2
8.5
10.8
13.1
15.4
17.7
20
LED Current (mA)
1.6
85
2
Accuracy (%)
3
VIN = 5V
83
VIN = 3.6V
81
VIN = 4.2V
80
79
1.6
15.4
17.7
20
IB1, B2, A1, A2, A3
0
-1
-3
3.9
6.2
8.5
10.8
20.0
13.1
15.4
17.7
2.7
20
19.2
19.0
I A3
I A2
18.6
3.4
3.8
4.1
4.5
4.8
5.2
5.5
4.5
Supply Voltage (V)
4.8
5.2
0.6
25°C
0.5
85°C
0.4
0.3
0.2
0.1
0.0
2.7
18.4
3.1
4.1
Supply Voltage (V)
Shutdown Current (µA)
19.4
I B2
3.8
0.7
I A1
18.8
3.4
Shutdown Current vs.
Supply Voltage and Temperature
I B1
19.6
3.1
19.8
LED Current (mA)
13.1
1
LED Current vs. Supply Voltage
6
10.8
-2
LED Current (mA)
2.7
8.5
LED Current Accuracy vs. Supply Voltage
86
82
6.2
LED Current (mA)
(Group A and B On)
84
3.9
Efficiency vs. LED Current
Efficiency (%)
VIN = 5V
83
Efficiency (%)
Efficiency (%)
82
5.5
-40°C
3.1
3.5
3.9
4.3
4.7
Supply Voltage (V)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
5.1
5.5
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Typical Characteristics
LED Current vs. Temperature
LED Current Accuracy vs. Temperature
(All Channels = 20mA)
(All Channels = 20mA)
LED Current (mA)
21.0
LED Current Accuracy (%)
21.2
IA3
20.8
20.6
20.4
20.2
IB1
IA2
IB2
20.0
19.8
19.6
19.4
IA1
19.2
19.0
-40
-15
10
35
60
4
3
2
1
0
IA2
-3
IB2, A1
-4
-5
-6
-40
-15
Output Voltage (top) (V)
Switching Node (middle) (V)
50
0
0
0.5
0
Time (50µs/div)
14.5
14.0
13.5
0V
1.0
0.5
0.0
Time (200ns/div)
Output Ripple
Switching Frequency vs.
Supply Voltage and Temperature
(All Channels = 10mA)
13.0
12.5
14V
0V
0.5
0.0
Switching Frequency (MHz)
13.5
Inductor Current (bottom) (A)
Output Voltage (top) (V)
Switching Node (middle) (V)
16V
Inductor Current (bottom) (A)
0
Time (200ns/div)
85
Output Ripple
50
IINDUCTOR (A)
60
(All Channels = 20mA)
5
IGROUP_B (mA)
35
Temperature (°C)
(All Channels)
IGROUP_A (mA)
10
Shutdown Operation
Enable (V)
IA3
-2
85
Temperature (°C)
IB1
-1
2.5
25°C
2.0
1.5
-40°C
1.0
+85°C
0.5
0.0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Supply Voltage (V)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
7
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Typical Characteristics
Line Transient
Enable Threshold Low vs.
Supply Voltage and Temperature
(All Channels = 20mA)
3.5
3.0
14.2
14.1
14.0
13.9
13.8
Enable Threshold Low (V)
Input Voltage (top) (V)
4.0
Output Voltage (bottom) (V)
4.5
1.1
1.0
-40°C
0.9
25°C
0.8
0.7
+85°C
0.6
2.7
Time (50µs/div)
4.3
4.7
5.1
5.5
Supply Voltage (V)
280
1.2
260
-40°C
+120°C
25°C
RDS(ON)IN (mΩ)
1.1
1.0
0.9
+85°C
+100°C
240
220
200
+85°C
180
+25°C
0.8
160
0.7
2.7
3.1
3.5
3.9
4.3
4.7
5.1
140
2.5
5.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Supply Voltage (V)
Low Side Switch On Resistance
vs. Supply Voltage and Temperature
Soft Start Operation
(All Channels = 20mA)
5
160
SCL (V)
140
RDS(ON)N (mΩ)
3.9
Input Disconnect Switch Resistance vs.
Supply Voltage and Temperature
Supply Voltage (V)
+120°C
SDA (V)
120
0
5
0
+100°C
14V
100
VOUT (V)
80
+25°C
40
2.5
0
0.5
+85°C
60
IINDUCTOR (A)
3.0
3.5
4.0
4.5
Supply Voltage (V)
8
3.5
Enable Threshold High vs.
Supply Voltage and Temperature
Enable Threshold High (V)
3.1
5.0
5.5
0
6.0
Time (200µs/div)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Typical Characteristics
Transition of LED Current
Transition of LED Current
(All Channels = 20mA to 1.8mA)
SCL (V)
SDA (V)
(Group A= 20mA to 1.8mA; Group B = 20mA)
5
0
5
0
0.05
IB1 (A)
0.05
SDA (V)
5
0
0
0.05
0
0.05
IA1 (A)
0
Time (100µs/div)
5
IB1 (A)
0
IA1 (A)
SCL (V)
0
Time (100µs/div)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
9
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Functional Block Diagram
LIN
SW
VIN
IN
OV
ROM
Boost
Converter
Control
V(A1, A2, A3)
VREF
V(B1, B2)
D/A
A1
D/A
A2
D/A
A3
D/A
B1
D/A
B2
ROM
VREF
EN
SCL
Max Current
Adjustment
I2C Interface
SDA
GND
Functional Description
The AAT1236 consists of a controller for the step-up
switching converter and its power switch, and five regulated current sinks programmable over 16 levels into two
groups, which can be turned on/off individually. An
external Schottky diode, a power inductor, an output
capacitor, and a resistor divider are required to complete
the solution.
The AAT1236’s boost controller is designed to deliver
100mA up to 24V. The AAT1236 is capable of driving a
total of five channels divided into two groups with four
white LEDs connected in series at each channel.
The output load current can be programmed by the current sink magnitudes. I2C interface programming allows
independent control of two groups of current sinks (A1
to A3 and B1 to B2) and control on/off with a different
configuration on each channel. Unused sink channel(s)
must be connected to AGND to ensure proper function of
the AAT1236.
Control Loop
The AAT1236 provides the benefits of current mode control with a simple hysteretic output current loop providing exceptional stability and fast response with minimal
design effort. The device maintains exceptional constant
current regulation, transient response, and cycle-by-
10
AGND
RSET
cycle current limit without additional compensation components.
The AAT1236 modulates the power MOSFET switching
current to maintain the programmed sink current
through each channel. The sink voltage at each channel
is monitored and the controller provides direct feedback
in order to maintain the desired LED currents.
The switching cycle initiates when the N-channel MOSFET
is turned ON and current ramps up in the inductor. The
ON interval is terminated when the inductor current
reaches the programmed peak current level. During the
OFF interval, the input current decays until the lower
threshold, or zero inductor current, is reached. The lower
current is equal to the peak current minus a preset hysteresis threshold, which determines the inductor ripple
current. Peak current is adjusted by the controller until
the desired LED output current level is met.
The magnitude of the feedback error signal determines
the average input current. Therefore, the AAT1236 controller implements a programmed current source connected to the output capacitor, parallel with the LED
channels. There is no right-half plane zero, and loop stability is achieved with no additional compensation components. The controller responds by increasing the peak
inductor current, resulting in higher average current in
the inductor and LED channels.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Under light load conditions, the inductor OFF interval
current goes below zero and the boost converter enters
discontinuous mode operation. Further reduction in the
load current results in a corresponding reduction in the
switching frequency. The AAT1236 provides pulsed frequency operation which reduces switching losses and
maintains high efficiency under light load conditions.
Operating frequency varies with changes in the input voltage, output voltage, and inductor size. Once the boost
converter has reached continuous mode, further increases in the LED current will not significantly change the
operating frequency. A small 2.2µH (±20%) inductor is
selected to maintain high frequency switching (up to
2MHz) and high efficiency operation for outputs up to
24V.
Soft Start / Enable
The input disconnect switch is activated when a valid
supply voltage is present and the EN/SET pin is strobed
high. Slew rate control on the input disconnect switch
ensures minimal inrush current as the output voltage is
charged to the input voltage, prior to switching of the
N-channel power MOSFET. A monotonic turn-on is guaranteed by the built-in soft-start circuitry, which eliminates output current overshoot across the full input
voltage range and over all load conditions.
Current Limit and
Over-Temperature Protection
The switching of the N-channel MOSFET terminates when
a current limit of 1.5A (typical) is exceeded. This minimizes power dissipation and component stresses under
overload and short-circuit conditions. Switching resumes
when the current decays below the current limit.
Thermal protection disables the AAT1236 when internal
power dissipation becomes excessive, as it disables both
MOSFETs. The junction over-temperature threshold is
140°C with 15°C of temperature hysteresis. The output
voltage automatically recovers when the over-temperature fault condition is removed.
Over-Voltage Protection
Over-voltage protection prevents damage to the AAT1236
during open-circuit on any LED channel causing high
output voltage conditions. An over-voltage event is
defined as a condition where the voltage on the OV pin
exceeds the over-voltage threshold limit (VOV = 1.2V
typical). When the voltage on the OV pin has reached
the threshold limit, the converter stops switching and
the output voltage decays. Switching resumes when the
voltage on the OV pin drops below the lower hysteresis
limit, maintaining an average output voltage between
the upper and lower OV thresholds multiplied by the
resistor divider scaling factor.
Under-Voltage Lockout
Internal bias of all circuits is controlled via the VIN input.
Under-voltage lockout (UVLO) guarantees sufficient VIN
bias and proper operation of all internal circuitry prior to
soft start.
I2C Serial Interface and Programmability
The current sink magnitude of each group and the on/off
status of each channel is controlled via an I2C serial
interface. I2C is a widely used interface which requires a
master to initiate all the communications with the
device. I2C protocol consists of two active wire SDA
(serial data line) and SCL (serial clock line). Both wires
are open drain and require an external pull-up resistor
to VCC. The SDA pin serves the I/O function, and the SCL
pin controls and references the I2C bus. The I2C protocol
is a bidirectional bus which allows both read and write
actions to take place; the AAT1236 supports the write
protocol only. Since the protocol has a dedicated bit for
Read or Write (R/W), when communicating with the
AAT1236, this bit must be set to “0.”
I2C Programming Register
Address and Register Data
After sending the device address, the I2C master should
send an 8-bit register address and 8-bit data for programming. The AAT1236 has two registers; the
Brightness Control Register determines the percentage
of the maximum current set by RSET applied to each
channel and the Channel Control Register determines
which channels are enabled or disabled. The programming is as follows:
BR_CRTL – LED Brightness Control Register
(Address: 00h)
BR_CTRL
Bit name
D7
BX3
D6
BX2
D5
BX1
D4
BX0
D3
AX3
D2
AX2
D1
AX1
D0
AX0
Control register BR_CRTL can be used to control LED
brightness for each group. Control bits BX3, BX2, BX1,
BX0 set the percentage of the maximum LED level in
Group B. Control bits AX3, AX2, AX1, AX0 set the percentage of the maximum LED level in Group A.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
11
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
BR_CTRL [BX3:BX0],
[AX3:AX0]
All Outputs (%)
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
100
84
71
60
51
43
35
31
26
21
18
15
13.5
12.0
10.5
9.0
CH_CRTL – Channel ON/OFF Control Register
(Address: 01h)
D7
–
D6
–
D5
–
D4
BY1
D3
BY2
D2
AY1
D1
AY2
D0
AY3
Control register CH_CRTL can be used to disable (OFF)
or enable (ON) individual channels.
CH_CTRL [BY1:BY2]
B1
B2
00
01
10
11
OFF
OFF
ON
ON
OFF
ON
OFF
ON
CH_CTRL [AY1:AY3]
A1
A2
A3
000
001
010
011
100
101
110
111
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
12
I2C Serial Interface
The AAT1236 is fully compliant with the industry-standard
I2C interface. The I2C two-wire communications bus consists of SDA and SCL lines. SDA provides data, while SCL
provides clock synchronization. SDA data transfers device
address followed by a register address and data bits
sequence. When using the I2C interface, EN/SET is pulled
high to enable the device or low to disable the device. The
I2C serial interface requires a master to initiate all the
communications with target devices. The AAT1236 is a
target device and only supports the write protocol. The
AAT1236 is manufactured with a target device address of
0x36 (Hex). See Figure 1 for the I2C interface diagram.
Table 1: LED Current Setting as Percentage of the
Maximum Level Set by RSET.
CH_CTRL
Bit name
Application Information
I2C START and STOP Conditions
START and STOP conditions are always generated by the
master. Prior to initiating a START, both the SDA and SCL
pins are in idle mode (idle mode is when there is no activity on the bus and both SDA and SCL are pulled high by
the external pull-up resistors). A START condition occurs
when the master pulls the SDA line low and, after a short
period, pulls the SCL line low. A START condition acts as
a signal to all ICs that transmission activity is about to
occur on the BUS. A STOP condition, as shown in Figure
2, is when the master releases the bus and SCL changes
from low to high followed by SDA low-to-high transition.
I2C Address Bit Map
Figure 3 illustrates the address bit transfer. The 7-bit
address is transferred with the Most Significant Bit (MSB)
first and is valid when SCL is high. This is followed by the
R/W bit in the Least Significant Bit (LSB) location. The
R/W bit determines the direction of the transfer (‘1’ for
read, ‘0’ for write). The AAT1236 is a write-only device
and this bit must be set low. The Acknowledge bit (ACK)
is set to low by the AAT1236 to acknowledge receipt of
the address.
I2C Register Address / Data Bit Map
Figure 4 illustrates the Register Address or the data bit
transfer. The 8-bit data is always transferred with the
most significant bit first and is valid when SCL is high. The
Acknowledge bit (ACK) is set low by the AAT1236 to
acknowledge receipt of the register address or the data.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
start
Device Address
w
ACK
Register Address
ACK
DATA
ACK
AAT1236 Device Addr = 36h
w
ACK
Address = 00h
ACK
Data = 06h
ACK
stop
SCL
SDA
start
stop
Figure 1: I2C Serial Interface Diagram.
START
STOP
SDA
SDA
SCL
SCL
TSU_STO
THD_STA
Figure 2: I2C Start and Stop Conditions;
START: A High “1” to Low “0” Transition on the SDA Line While SCL is High “1”
STOP: A Low “0” to High “1” Transition on the SDA Line While SCL is High “1.”
SCL
1
2
3
4
5
6
7
MSB
SDA
A6
8
9
LSB
A5
A4
A3
A2
A1
A0
R/W
ACK
Device Address
Figure 3: I2C Device Address Bit;
7-bit Slave Address (A6-A0), 1-bit Read/Write (R/W), 1-bit Acknowledge (ACK).
SCL
1
2
3
4
5
6
7
MSB
SDA
D7
8
9
LSB
D6
D5
D4
D3
D2
D1
D0
ACK
Register Address /
Data
Figure 4: I2C Register Address and Data Bit Map;
8-bit Data (D7-D0), 1-bit Acknowledge (ACK).
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
13
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
I2C Acknowledge Bit (ACK)
8. Send the CH_CTRL register address (0x01)
9. Wait for the ACK bit within the clock cycle
10.Send the CH_CTRL Data (0x1F)
11.Wait for the ACK bit within the clock cycle
12.Send the stop condition
The Acknowledge bit is the ninth bit of each transfer on
the SDA line. It is used to send back a confirmation to the
master that the data has been received properly by the
target device. For each ACK to take place, the master
must first release the SDA line, then the target device will
pull the SDA line low, as shown in Figures 1, 3 and 4.
Example 2:
Turn on A1 and A3 with 43% for the max LED current setting and turn on Group B with 100% for the max LED
current setting. Figure 6 shows the I2C transfer protocol.
I2C Software Protocol Example
The AAT1236 I2C programming protocol is shown in the
following two examples, detailing the device address,
register address and data bits. Figure 5 shows the I2C
transfer protocol.
1. Send a start condition
2. Send the AAT1236’s I2C device address (0x36) with
the R/W bit set low
3. Wait for the acknowledge (ACK) bit within the clock
cycle
4. Send the BR_CTRL register address (0x00)
5. Wait for the ACK bit within the clock cycle
6. Send the BR_CTRL Data (0x05)
7. Wait for the ACK bit within the clock cycle
8. Send the CH_CTRL register address (0x01)
9. Wait for the ACK bit within the clock cycle
10.Send the CH_CTRL Data (0x1D)
11.Wait for the ACK bit within the clock cycle
12.Send the stop condition
Example 1:
Turn on Group A with 15% from the max current setting
and turn on Group B with 51% from the max current
setting.
1. Send a start condition
2. Send the AAT1236’s I2C device address (0x36) with
the R/W bit set low
3. Wait for the acknowledge (ACK) bit within the clock
cycle
4. Send the BR_CTRL register address (0x00)
5. Wait for the ACK bit within the clock cycle
6. Send the BR_CTRL Data (0x4B)
7. Wait for the ACK bit within the clock cycle
S
T
A
R
T
Device Address
(Write)
0
SDA
A
C
K
1
1
0 1
1
0
0
0
0
0 0
0
Tie all unused channels to AGND. On start-up these
channels will be automatically disabled.
A
C
K
Register Address
0 0
Channel Disable
0
A
C
K
Data
0 1
0
0 1
0 1
1
A
C
K
Register Address
0 0
0
0
0 0
0
1
S
A T
C O
K P
Data
0 0
0
1 1
1 1
1
Figure 5: I2C Transfer Protocol for Example 1.
SDA
S
T
A
R
T
A
C
K
Device Address
(Write)
0
1
1
0 1
1
0
0
A
C
K
Register Address
0 0
0
0
0 0
0
0
A
C
K
Data
0 0
0
0 0
1 0
1
A
C
K
Register Address
0 0
0
0
0 0
0
1
Data
0 0
0
1 1
Figure 6: I2C Transfer Protocol for Example 2.
14
S
A T
C O
K P
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
1 0
1
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
LED Selection
Although the AAT1236 is specifically designed to drive
white LEDs, the device can also be used to drive most
types of LEDs with forward voltages ranging between
2.0V and 4.7V. Since the A1, A2, A3, and B1, B2 input
current sinks are matched with low voltage dependence,
the LED-to-LED brightness will be matched regardless of
the individual LED forward voltage (VF) levels. In some
instances, it may be necessary to drive high-VF type
LEDs. The low dropout (~0.1V @ 20mA ILED) current sinks
in the AAT1236 make it capable of driving LEDs with forward voltages as high as 4.7V from an input supply as low
as 3.0V. LED outputs A1-A3 and B1-B2 can be combined
to drive high-current LEDs without complication, making
the AAT1236 a perfect application for large LCD display
backlighting and keypad LED applications.
ILED (mA)
RSET (kW)
30
25
20
15
10
5
14.7
17.4
22.6
29.4
44.2
93.1
Table 2: Maximum LED Current and RSET Resistor
Values (1% Resistor Tolerance).
Maximum LED current per channel versus RSET value is
shown in Figure 7.
35
LED Current (mA)
30
Constant Current Setting
The LED current is controlled by the RSET resistor. For
maximum accuracy, a 1% tolerance resistor is recommended. Table 2 shows the RSET resistor value for
AAT1236 for various LED full-scale current levels.
25
20
15
10
5
0
10
36
62
88
114
140
166
192
218
244
270
RSET (kΩ)
Figure 7: LED Current vs. RSET Values.
VOUT
JP1
0
JP2
0
JP3
0
JP4
0
JP5
0
LED1
LED6
LED11
LED16
LED21
LED2
LED7
LED12
LED17
LED22
LED13
LED18
LED23
LED14
LED19
LED24
JP8
0
JP9
0
JP10
0
D1
MBR0530T1
LED3
LED8
SW_Node
R2
187k
LED4
LED9
JP6
0
JP7
0 U1
VIN
JP6
3
2
1
C1
2.2µF
Enable/Set
R4
4.7k
(optional)
JP7
SDA
SCL
R5
4.7k
(optional)
R3
12.1k
R1
22.6k
1
2
3
4
5
6
7
8
L1
2.2µH
VIN
LIN
OV
A1
EN
A2
B1
A3
B2
AGND
RSET
SCL
IN
SDA
GND
SW
16
15
14
13
12
11
10
9
C2
2.2µF
25V
RTN
AAT1236_TDFN3X4
2
1
L1: 2.2µH Taiyo Yuden NR4018T2R2M
C1: 0805 10V 2.2µF X7R GRM21BR71A225KA01
C2: 0805 25V 2.2µF X7R GRM21BR71E225KA73L
LED1-24: OSRAM LW M673 or equivalent
Figure 8: A AAT1236-based High Efficiency White LED Driver Schematic.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
15
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Over-Voltage Protection
The over-voltage protection circuit consists of a resistor
network connected from the output voltage to the OV pin
(see Figure 9). This over voltage protection circuit prevents damage to the device when one of the five channels has an open LED circuit. The AAT1236 continues to
operate; however, the LED current in the remaining
channels is no longer regulated and the actual LED current will be determined by the externally programmed
over-voltage protection threshold, the inductor value,
and the switching frequency.
The resistor divider can be selected such that the overvoltage threshold occurs prior to the output reaching
24V (VOUT(MAX)). The value of R3 should be selected from
10kW to 20kW to minimize switching losses without
degrading noise immunity.
R2 = R3 ·
VOUT(PROTECTION)
-1
VOV
VOUT
R2
COUT
OV
R3
Figure 9: Over-Voltage Protection Circuit.
If four LEDs are connected in series on one channel, the
total VF from the WLEDs could be as high as 18.8V.
Therefore, using R3 = 12.1kW and setting VOUT(PROTECTION) =
20V is recommended. Selecting a 1% resistor, this results
in R2 = 187kW (rounded to the nearest standard 1%
value).
It is always recommended to use the same number of
WLEDs on each channel and set the appropriate overvoltage protection. Failure to do so may cause any one
of the (5) sink pins to exceed the absolute maximum
16
Number
of WLEDs
on Each
Channel
Total
Maximum
VF (V)
VOUT(PROTECTION)
(V)
R3 = 12.1kW
R2 (kW)
4
3
2
18.8
14.1
9.4
20
15
10
187
140
88.7
Table 3: Over-Voltage Protection Settings.
LED Brightness Control
The AAT1236 uses the I2C interface to program and control LED brightness. The output current of the AAT1236
can be changed successively to brighten or dim the LEDs
in smooth transitions (i.e., to fade in or fade out) or in
discrete steps, giving the user complete programmability
and real-time control of LED brightness.
Selecting the Schottky Diode
AAT1236
GND
rating voltage and permanently damage the device in
case the channel is disconnected (open circuit failure).
Examples of over voltage settings for various strings of
series-connected LEDs are shown in Table 3.
To ensure minimum forward voltage drop and no recovery, high voltage Schottky diodes are recommended for
the AAT1236 boost converter. The output diode is selected to maintain acceptable efficiency and reasonable
operating junction temperature under full load operating
conditions. Forward voltage (VF) and package thermal
resistance (qJA) are the dominant factors in selecting a
diode. The diode non-repetitive peak forward surge current rating (IFSM) should be considered for high pulsed
load applications, such as camera flash. IFSM rating drops
with increasing conduction period. Manufacturers’
datasheets should be reviewed carefully to verify reliability under peak loading conditions. The diode’s published current rating may not reflect actual operating
conditions and should be used only as a comparative
measure between similarly rated devices.
20V rated Schottky diodes are recommended for output
voltages less than 15V, while 30V rated Schottky diodes
are recommended for output voltages higher than 15V.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Estimating Schottky Diode
Power Dissipation
The switching period is divided between ON and OFF
time intervals:
1
= TON + TOFF
FS
During the ON time, the N-channel power MOSFET is
conducting and storing energy in the boost inductor.
During the OFF time, the N-channel power MOSFET is
not conducting. Stored energy is transferred from the
input battery and boost inductor to the output load
through the output diode.
Duty cycle is defined as the ON time divided by the total
switching interval:
TON
D=
TON + TOFF
= TON ⋅ FS
The maximum duty cycle can be estimated from the
relationship for a continuous mode boost converter.
Maximum duty cycle (DMAX) is the duty cycle at minimum
input voltage (VIN(MIN)):
DMAX =
VOUT - VIN(MIN)
VOUT
The average diode current during the OFF time can be
estimated:
IAVG(OFF) =
IOUT
1 - DMAX
The VF of the Schottky diode can be estimated from the
average current during the off time. The average diode
current is equal to the output current:
IAVG(TOT) = IOUT
The average output current multiplied by the forward
diode voltage determines the loss of the output diode:
PLOSS(DIODE) = IAVG(TOT) · VF
= IOUT · VF
For continuous LED currents, the diode junction temperature can then be estimated:
TJ(DIODE) = TAMB + θJA · PLOSS(DIODE)
External Schottky diode junction temperature should be
below 110ºC, and may vary depending on application
and/or system guidelines. The diode qJA can be minimized with additional metal PCB area on the cathode.
However, adding additional heat-sinking metal around
the anode may degrade EMI performance. The reverse
leakage current of the rectifier must be considered to
maintain low quiescent (input) current and high efficiency under light load. The rectifier reverse current
increases dramatically at elevated temperatures.
Selecting the Boost Inductor
The AAT1236 controllers utilize hysteretic control and the
switching frequency varies with output load and input
voltage. The value of the inductor determines the maximum switching frequency of the boost converter.
Increased output inductance decreases the switching
frequency, resulting in higher peak currents and increased
output voltage ripple. To maintain 2MHz maximum
switching frequency and stable operation, an output
inductor selected between 1.5µH and 2.7µH is recommended.
Manufacturer
Part Number
Rated IF(AV)
Current (A)
Rated
Voltage (V)
Thermal Resistance
(qJA, °C/W)
Case
Diodes, Inc.
ON Semi
ON Semi
B0520WS
MBR130LSFT
MBR0530T
0.50
1.00
0.50
20
30
30
426
325
206
SOD-323
SOD-123
SOD-123
Table 4: Typical Surface Mount Schottky Rectifiers for Various Output Loads
(select TJ < 110°C in application circuit).
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
17
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
A better estimate of DMAX is possible once VF is known:
DMAX =
(VOUT + VF - VIN(MIN))
(VOUT + VF)
Where VF is the Schottky diode forward voltage. If not
known or not provided by the manufacturer, a starting
value of 0.5V can be used.
Manufacturer’s specifications list both the inductor DC
current rating, which is a thermal limitation, and peak
inductor current rating, which is determined by the saturation characteristics. Measurements at full load and
high ambient temperature should be performed to
ensure that the inductor does not saturate or exhibit
excessive temperature rise.
The output inductor (L) is selected to avoid saturation at
minimum input voltage and maximum output load conditions. Peak current may be estimated using the following
equation, assuming continuous conduction mode. Worstcase peak current occurs at minimum input voltage
(maximum duty cycle) and maximum load. Switching
frequency (FS) can be estimated at 500kHz with a 2.2µH
inductor:
IPEAK =
IOUT
D
· VIN(MIN)
+ MAX
(1 - DMAX)
(2 · FS · L)
At light load and low output voltage, the controller reduces the operating frequency to maintain maximum operating efficiency. As a result, further reduction in output load
does not reduce the peak current. Minimum peak current
can be estimated between 0.5A and 0.75A.
At high load and high output voltages, the switching frequency is somewhat diminished, resulting in higher IPEAK.
Bench measurements are recommended to confirm
actual IPEAK and to ensure that the inductor does not
saturate at maximum LED current and minimum input
supply voltage.
The RMS current flowing through the boost inductor is
equal to the DC plus AC ripple components. Under worstcase RMS conditions, the current waveform is critically
continuous. The resulting RMS calculation yields worstcase inductor loss. The RMS current value should be
compared against the inductor manufacturer’s temperature rise, or thermal derating, guidelines:
IRMS =
18
IPEAK
3
For a given inductor type, smaller inductor size leads to
an increase in DCR winding resistance and, in most
cases, increased thermal impedance. Winding resistance
degrades boost converter efficiency and increases the
inductor’s operating temperature:
PLOSS(INDUCTOR) = IRMS2 · DCR
To ensure high reliability, the inductor case temperature
should not exceed 100ºC. In some cases, PCB heatsinking applied to the LIN node (non-switching) can improve
the inductor’s thermal capability. However, as in the case
of adding extra metal around the Schottky’s anode, adding extra PCB metal around the AAT1236’s SW pin for
heatsinking may degrade EMI performance.
Shielded inductors provide decreased EMI and may be
required in noise sensitive applications. Unshielded chip
inductors provide significant space savings at a reduced
cost compared to shielded (wound and gapped) inductors. In general, chip-type inductors have increased
winding resistance (DCR) when compared to shielded,
wound varieties.
Selecting the Boost Capacitors
The high output ripple inherent in the boost converter
necessitates the use of low impedance output filtering.
Multi-layer ceramic (MLC) capacitors provide small size
and adequate capacitance, low parasitic equivalent
series resistance (ESR) and equivalent series inductance
(ESL), and are well suited for use with the AAT1236
boost regulator. MLC capacitors of type X7R or X5R are
recommended to ensure good capacitance stability over
the full operating temperature range.
The output capacitor is selected to maintain the output
load without significant voltage droop (DVOUT) during the
power switch ON interval, when the output diode is not
conducting. A ceramic output capacitor from 2.2µF to
4.7µF is recommended (see Table 6).
Typically, 25V rated capacitors are required for the 24V
maximum boost output. Ceramic capacitors selected as
small as 0805 are available which meet these requirements.
MLC capacitors exhibit significant capacitance reduction
with applied voltage. Output ripple measurements should
confirm that output voltage droop and operating stability
are within acceptable limits. Voltage derating can minimize this factor, but results may vary with package size
and among specific manufacturers.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Manufacturer
Part Number
Inductance (µH)
Max DC ISAT
Current (A)
DCR (W)
Size (mm)
LxWxH
Type
Sumida
Sumida
Sumida
Murata
Murata
Taiyo Yuden
Taiyo Yuden
Coiltronics
Coiltronics
Coiltronics
CDRH4D22/HP-2R2
CDR4D11/HP-2R4
CDRH4D18-2R2
LQH662N2R2M03
LQH55DN2R2M03
NR4018T2R2
NR3015T2R2
SD3814-2R2
SD3114-2R2
SD3112-2R2
2.2
2.4
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.50
1.70
1.32
3.30
3.20
2.70
1.48
1.90
1.48
1.12
35
105
75
19
29
60
60
77
86
140
5.0x5.0x2.4
4.8x4.8x1.2
5.0x5.0x2.0
6.3x6.3x4.7
5.0x5.7x4.7
4.0x4.0x1.8
3.0x3.0x1.5
3.8x3.8x1.4
3.1x3.1x1.4
3.1x3.1x1.2
Shielded
Shielded
Shielded
Shielded
Non-Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Table 5: Typical Surface Mount Inductors for Various Output Loads (select IPEAK < ISAT).
Manufacturer
Part Number
Value (µF)
Voltage Rating
Temp Co
Case Size
Murata
Murata
Murata
Murata
Murata
GRM188R60J225KE19
GRM21BR71A225KA01
GRM219R61E225KA12
GRM21BR71E225KA73L
GRM21BR61E475KA12
2.2
2.2
2.2
2.2
4.7
6.3
10
25
25
25
X5R
X7R
X5R
X7R
X5R
0603
0805
0805
0805
0805
Table 6: Recommended Ceramic Capacitors.
Output capacitor size can be estimated at a switching
frequency (FS) of 500kHz (worst case):
COUT =
IOUT · DMAX
FS · ∆VOUT
To maintain stable operation at full load, the output
capacitor should be selected to maintain DVOUT between
100mV and 200mV.
The boost converter input current flows during both ON
and OFF switching intervals. The input ripple current is
less than the output ripple and, as a result, less input
capacitance is required.
PCB Layout Guidelines
Boost converter performance can be adversely affected
by poor layout. Possible impacts include high input and
output voltage ripple, poor EMI performance, and reduced
operating efficiency. Every attempt should be made to
optimize the layout in order to minimize parasitic PCB
effects (stray resistance, capacitance, and inductance)
and EMI coupling from the high frequency SW node. A
suggested PCB layout for the AAT1236 boost converter is
shown in Figures 10 and 11. The following PCB layout
guidelines should be considered:
1. Minimize the distance from Capacitor C1 and C2’s
negative terminals to the GND pins. This is especially true with output capacitor C2, which conducts
high ripple current from the output diode back to the
GND pins.
2. Minimize the distance between L1 to D1 and switching pin SW; minimize the size of the PCB area connected to the SW pin.
3. Maintain a ground plane and connect to the IC GND
pin(s) as well as the GND connections of C1 and C2.
4. Consider additional PCB metal area on D1’s cathode
to maximize heatsinking capability. This may be necessary when using a diode with a high VF and/or
thermal resistance.
5. Do not connect the exposed paddle (bottom of the
die) to either AGND or GND because it is connected
internally to SW. Connect the exposed paddle to the
SW pin or leave floating.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
19
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Figure 10: AAT1236 Evaluation Board
Top Side Layout.
Figure 11: AAT1236 Evaluation Board
Bottom Side Layout.
Figure 12: Exploded View of AAT1236 Evaluation Board
Top Side Layout Detailing Plated Through Vias.
20
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
TDFN34-16
UDXYY
AAT1236IRN-T1
Skyworks Green™ products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of Green™, document number
SQ04-0074.
Package Information3
TDFN34-16
3.000 ± 0.050
1.600 ± 0.050
Detail "A"
3.300 ± 0.050
4.000 ± 0.050
Index Area
0.350 ± 0.100
Top View
0.230 ± 0.050
Bottom View
C0.3
(4x)
0.050 ± 0.050
0.450 ± 0.050
0.850 MAX
Pin 1 Indicator
(optional)
0.229 ± 0.051
Side View
Detail "A"
All dimensions in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3.The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing
process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
21
DATA SHEET
AAT1236
High Efficiency White LED Drivers for Backlight and Keypad
Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved.
Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. These materials, including the information contained herein, are provided by Skyworks as a
service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Skyworks may change its documentation, products, services, specifications or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no
responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from any future changes.
No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided hereunder, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale.
THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR
PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES
NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES, INCLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM
THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the Skyworks products could lead to personal injury, death, physical or environmental damage. Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper
use or sale.
Customers are responsible for their products and applications using Skyworks products, which may deviate from published specifications as a result of design defects, errors, or operation of products outside of published parameters or design specifications. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product
design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters.
Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for
identification purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference.
22
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202111A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012