PRODUCT DATASHEET
AAT1239-1
SwitchReg
TM
General Description
The AAT1239-1 is a high frequency, high efficiency con-
stant current boost converter capable of driving up to
ten (10) series-connected white LEDs or 40V. It is an
ideal power solutions for backlight applications with up
to ten white LEDs in series. The input voltage is 2.7V to
5.5V for single-cell lithium-ion/polymer (Li-ion) based
portable devices.
The LED current is digitally controlled across a 6x oper-
ating range using AnalogicTech’s Simple Serial Control™
(S
2
Cwire™) interface. Programmability across 26 dis-
crete current steps provides high resolution, low noise,
flicker-free, constant LED outputs. In programming
AAT1239 operation, LED brightness increases based on
the data applied at the EN/SET pin. The SEL logic pin
changes the feedback voltage between two program-
mable ranges.
The AAT1239-1 features a high current limit and fast,
stable transitions for stepped or pulsed current applica-
tions. The high switching frequency (up to 2MHz) pro-
vides fast response and allows the use of ultra-small
external components, including chip inductors and
capacitors. Fully integrated control circuitry simplifies
design and reduces total solution size. The AAT1239-1
offers a true load disconnect feature which isolates the
load from the power source while in the OFF or disabled
state. This eliminates leakage current, making the devic-
es ideally suited for battery-powered applications.
The AAT1239-1 is available in the Pb-free, thermally-
enhanced 12-pin TSOPJW package.
40V Step-Up Converter for 4 to 10 White LEDs
Features
• Input Voltage Range: 2.7V to 5.5V
• Maximum Continuous Output 40V @ 30mA
• Drives up to 10 LEDs in Series
▪
Constant LED Current with 3.5% Accuracy Over
Temperature and Input Voltage Range
• Digital Control with S
2
Cwire Single Wire Interface
▪
26 Discrete Steps
▪
No PWM Control Required
▪
No Additional Circuitry
• Up to 85% Efficiency
• Up to 2MHz Switching Frequency Allows Small External
Chip Inductor and Capacitors
• Hysteretic Control
▪
No External Compensation Components
▪
Excellent Load Transient Response
▪
High Efficiency at Light Loads
• Integrated Soft Start with No External Capacitor
• True Load Disconnect Guarantees <1.0μA Shutdown
Current
• Selectable Feedback Voltage Ranges for High Resolution
Control of Load Current
• Short-Circuit, Over-Voltage, and Over-Temperature
Protection
• 12-Pin TSOPJW Package
• -40°C to +85°C Temperature Range
Applications
•
•
•
•
•
Color Display Backlight
Digital Still Cameras (DSCs)
Digital Photo Frames
PDAs and Notebook PCs
White LED Drivers
Typical Application
L1
2.2μH
DS1
SS16L or equivalent
PVIN
Li-Ion:
V
IN
= 2.7V to 4.2V
C1
2.2μF
LIN
SW
C2
2.2μF
M673
R2
374k
VIN
AAT1239-1
OVP
Enable/Set
Feedback Voltage
Select
EN/SET
SEL
FB
PGND
AGND
I
LED
20mA
R3
12k
R1 (R
BALLAST
)
30.1
White LEDs
OSRAM LW M678
or equivalent
1239-1.2008.10.1.2
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1
PRODUCT DATASHEET
AAT1239-1
SwitchReg
TM
Pin Descriptions
Pin #
1
2
3
4
5
6, 7
8
9
10
11
12
40V Step-Up Converter for 4 to 10 White LEDs
Symbol
PVIN
EN/SET
SEL
VIN
N/C
SW
PGND
AGND
FB
OVP
LIN
Function
Input power pin; connected to the source of the P-channel MOSFET. Connect to the input capacitor(s).
IC enable pin and S
2
Cwire input control to set output current.
FB voltage range select. A logic LOW sets the FB voltage range from 0.4V to 0.1V; a logic HIGH sets the
FB voltage range from 0.6V to 0.3V.
Input voltage for the converter. Connect directly to the PVIN pin.
No connection.
Boost converter switching node. Connect the power inductor between this pin and LIN.
Power ground for the boost converter.
Ground pin.
Feedback pin. Connect a resistor to ground to set the maximum LED current.
Feedback pin for over-voltage protection sense.
Switched power input. Connect the power inductor between this pin and SW.
Pin Configuration
TSOPJW-12
(Top View)
PVIN
EN/SET
SEL
VIN
N/C
SW
1
2
3
4
5
6
12
11
10
9
8
7
LIN
OVP
FB
AGND
PGND
SW
2
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1239-1.2008.10.1.2
PRODUCT DATASHEET
AAT1239-1
SwitchReg
TM
Part Number Descriptions
Part Number
AAT1239ITP-1
SEL Polarity
HIGH
0.6V
≥
V
FB
≥
0.3V
LOW
0.4V
≥
V
FB
≥
0.1V
40V Step-Up Converter for 4 to 10 White LEDs
S
2
C Feedback Voltage Programming
See Table 2
Absolute Maximum Ratings
1
T
A
= 25°C unless otherwise noted.
Symbol
PVIN, VIN
SW
LIN, EN/SET, SEL, FB
T
J
T
S
T
LEAD
Description
Input Voltage
Switching Node
Maximum Rating
Operating Temperature Range
Storage Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Value
-0.3 to 6.0
45
V
IN
+ 0.3
-40 to 150
-65 to 150
300
Units
V
V
V
°C
°C
°C
Thermal Information
Symbol
θ
JA
P
D
Description
Thermal Resistance
Maximum Power Dissipation
Value
160
625
Units
°C/W
mW
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.
1239-1.2008.10.1.2
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3
PRODUCT DATASHEET
AAT1239-1
SwitchReg
TM
Electrical Characteristics
1
T
A
= -40°C to +85°C unless otherwise noted. Typical values are at 25°C, V
IN
= 3.6V.
Symbol
Power Supply
PV
IN
, V
IN
V
OUT(MAX)
I
Q
I
SHDN
I
OUT
ΔV
LINEREG(FB)
/ΔV
IN
R
DS(ON) L
R
DS(ON) IN
T
SS
V
OVP
I
LIMIT
T
SD
T
HYS
SEL, EN/SET
V
SEL(L)
V
SEL(H)
V
EN/SET(L)
V
EN/SET(H)
T
EN/SET (LO)
T
EN/SET(HI)
T
OFF
T
LAT
I
EN/SET
AAT1239-1
V
FB
FB Pin Regulation
V
IN
= 2.7V to 5.5V, SEL = GND,
EN/SET = DATA16
V
IN
= 2.7V to 5.5V, SEL = HIGH,
EN/SET = HIGH
0.085
0.54
0.1
0.6
1.115
V
0.66
40V Step-Up Converter for 4 to 10 White LEDs
Description
Input Voltage Range
Maximum Output Voltage
Operating Current
Shutdown Current
Maximum Continuous Output
Current
2
Line Regulation
Low Side Switch On Resistance
Input Disconnect Switch
On Resistance
Soft-Start Time
Over-Voltage Protection Threshold
Over-Voltage Hysteresis
N-Channel Current Limit
T
J
Thermal Shutdown Threshold
T
J
Thermal Shutdown Hysteresis
SEL Threshold Low
SEL Threshold High
Enable Threshold Low
Enable Threshold High
EN/SET Low Time
EN/SET High Time
EN/SET Off Timeout
EN/SET Latch Timeout
EN/SET Input Leakage
Conditions
Min
2.7
Typ
Max
5.5
40
70
1.0
30
Units
V
V
μA
μA
mA
%
mΩ
mΩ
μs
SEL = GND, FB = 0.1V
EN/SET = GND
2.7V < V
IN
< 5.5V, V
OUT
= 40V
V
IN
= 2.7V to 5.5V, V
FB
= 0.6V
0.7
135
180
From Enable to Output Regulation;
V
FB
= 300mV
V
OUT
Rising
V
OUT
Falling
400
1.1
1.2
100
2.5
140
15
1.3
V
mV
A
°C
°C
V
V
V
V
μs
μs
μs
μs
μA
0.4
1.4
0.4
V
EN/SET
V
EN/SET
V
EN/SET
V
EN/SET
V
EN/SET
<
>
<
>
=
0.6V
1.4V
0.6V
1.4V
5V V
IN
= 5V
1.4
0.3
75
75
500
500
1
-1
1. Specification over the -40°C to +85°C operating temperature range is assured by design, characterization, and correlation with statistical process controls.
2. Maximum continuous output current increases with reduced output voltage, but may vary depending on operating efficiency and thermal limitations.
4
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1239-1.2008.10.1.2
Analogue and Mixed Signal
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