General Description
The AAT3134 is a low noise, constant frequency
charge pump DC/DC converter that uses a dual
mode load switch (1X) and fractional (1.5X) con-
version to maximize efficiency for white LED appli-
cations. The device can be used to produce current
levels up to 20mA in each of its six outputs to drive
LEDs from a 2.7V to 5.5V input. Outputs may be
operated individually or paralleled for driving high-
er-current LEDs. A low external parts count (two
1F flying capacitors and two small 1F capacitors
at V
IN
and OUT) make the AAT3134 ideally suited
for small battery-powered applications.
AnalogicTech's Simple Serial ControlTM (S
2
CwireTM)
interface is used to enable, disable, and set the
LED drive current in two groups of four outputs and
two outputs with multiple-level, independently-con-
trolled brightness scales. The AAT3134 has a ther-
mal management system to protect the device in
the event of a short-circuit condition at the output
pin. Built-in soft-start circuitry prevents excessive
inrush current during start-up. A high charge pump
switching frequency enables the use of very small
external capacitors. A low-current shutdown feature
disconnects the load from V
IN
and reduces quies-
cent current to less than 1A. The AAT3134 is
available in a Pb-free 16-pin QFN44 package and is
rated over the -40C to +85C temperature range.
Features
V
IN
Range: 2.7V to 5.5V
<1.0A of Shutdown
1MHz Switching Frequency
Fully Independent Display Lighting
Dual Mode 1X and 1.5X Charge Pump for
Maximum Efficiency
Drives Low-V
F
and High-V
F
Type LEDs
Up to Six 20mA Outputs
Multi-Position Brightness Scale with Digital
Control
Low Noise Constant Frequency Operation
Small Application Circuit
Regulated Output Current
Automatic Soft Start
No Inductors
16-Pin QFN44 Package
-40C to +85C Temperature Range
Applications
Color (RGB) Lighting
Programmable Current Source
White LED Backlighting
White LED Photo Flash for Digital Still Cameras
AAT3134
High Efficiency 1X/1.5X Fractional
Charge Pump for White LED Applications
Typical Application
C
IN
1
F
V
BATTERY
C
OUT
1
F
EN/SET
C1
1
F
C2
1
F
D3
D2
D1
D6
VIN
VOUT
C1+
C1-
C2+
C2-
D1
D2
D3
D5
EN/SET
GND
AAT3134
D4
D5
D6
D4
Main
Display
Sub
Display
3134.2005.12.1.1
1
ChargePump
TM
Pin Descriptions
Pin Configuration
QFN44-16
(Top View)
1
2
3
4
12
11
10
9
5
6
7
8
16
15
14
13
D2
D5
D6
D3
D4
C1+
C1-
N/C
OUT
C2+
C2-
GND
N/C
IN
EN/SET
D1
Pin #
Symbol
Function
1
D2
Current source output #2.
2
D5
Current source output #5.
3
D6
Current source output #6.
4
D3
Current source output #3.
5
D4
Current source output #4.
6
C1+
Flying capacitor 1 positive terminal. Connect a 1F capacitor between C1+ and C1-.
7
C1-
Flying capacitor 1 negative terminal.
8,13
N/C
No connection.
9
OUT
Charge pump output. Requires 1F capacitor connected between this pin and ground.
10
C2+
Flying capacitor 2 positive terminal. Connect a 1F capacitor between C2+ and C2-.
11
C2-
Flying capacitor 2 negative terminal.
12
GND
Ground.
14
IN
Input power supply. Requires 1F capacitor connected between this pin and ground.
15
EN/SET
Control pin.
16
D1
Current source output #1.
EP
Exposed paddle (bottom); connect to GND directly beneath package.
AAT3134
High Efficiency 1X/1.5X Fractional
Charge Pump for White LED Applications
2
3134.2005.12.1.1
Absolute Maximum Ratings
1
Thermal Information
3
Symbol
Description
Value
Units
JA
Thermal Resistance
50
C/W
JC
Thermal Resistance
15
P
D
Maximum Power Dissipation
2
W
Symbol
Description
Value
Units
V
IN
Input Voltage
-0.3 to 6.0
V
V
OUT
Charge Pump Output
-0.3 to 6.0
V
FB, V
EN/SET
FB or EN/SET to GND Voltage
-0.3 to 6.0
V
V
EN/SET(MAX)
Maximum EN/SET to Input Voltage
0.3
V
I
OUT
2
Maximum DC Output Current
150
mA
T
J
Operating Junction Temperature Range
-40 to 150
C
AAT3134
High Efficiency 1X/1.5X Fractional
Charge Pump for White LED Applications
3134.2005.12.1.1
3
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-
tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Based on long-term current density limitation.
3. Mounted on an FR4 board.
Electrical Characteristics
1
V
IN
= 3.5V, C
IN
= C
OUT
= C
1
= C
2
= 1.0F; T
A
= -40C to +85C.
Unless otherwise noted, typical values are T
A
= 25C.
Symbol
Description
Conditions
Min
Typ
Max Units
Input Power Supply
V
IN
Operation Range
2.7
5.5
V
I
CC
Operating Current
3.0
V
IN
5.5, Active,
1.8
3.5
mA
No Load Current
I
SHDN
Shutdown Current
EN/SET = 0
1.0
A
I
DX(MAX)
Maximum Output Current
V
IN
= 3.6, Code = 32
18
20
22
mA
I
(D-Match)
Current Matching Between
VD1:D4 = 3.6, V
IN
= 3.5V
0.5
%
Any Two Outputs
VD5:VD6 = 3.6, V
IN
= 3.5V
0.5
Charge Pump Section
T
SS
Soft-Start Time
200
s
F
CLK
Clock Frequency
1000
kHz
CP
Charge Pump Section Efficiency
V
IN
= 3.5V, I
OUT(TOTAL)
= 120mA,
93
%
Measured from IN to OUT
EN/SET
V
EN(L)
Enable Threshold Low
0.5
V
V
EN(H)
Enable Threshold High
1.4
V
T
EN/SET LO
EN/SET Low Time
V
EN/SET
< 0.5
0.3
75
s
T
EN/SET HI
Minimum EN/SET High Time
V
EN/SET
> 1.4
50
ns
T
OFF
EN/SET Off Timeout
V
EN/SET
< 0.5
500
s
Input Current
EN/SET Input Leakage
-1.0
1.0
A
AAT3134
High Efficiency 1X/1.5X Fractional
Charge Pump for White LED Applications
4
3134.2005.12.1.1
1. The AAT3134 is guaranteed to meet performance specifications over the -40C to +85C operating temperature range and is assured
by design, characterization, and correlation with statistical process controls.
AAT3134
High Efficiency 1X/1.5X Fractional
Charge Pump for White LED Applications
3134.2005.12.1.1
5
Typical Characteristics
Unless otherwise noted, V
IN
= 3.5V, C
IN
= C
OUT
= C
1
= C
2
= 1F, T
A
= 25C.
V
IH
and V
IL
vs. V
IN
0.600
0.625
0.650
0.675
0.700
0.725
0.750
0.775
0.800
0.825
0.850
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
V
IH
V
IL
Quiescent Current vs. Input Voltage
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.50
3.00
3.50
4.00
4.50
5.00
5.50
Input Voltage
(V)
Quiescent Current (mA)
V
DIODE
= 3.3V
V
DIODE
= 3.4V
V
DIODE
= 3.5V
V
DIODE
= 3.6V
I
DIODE
vs. Input Voltage
(4x20mA)
40
45
50
55
60
65
70
75
80
85
90
2.7 2.9
3.1 3.3
3.5
3.7
3.9
4.1 4.3
4.5
4.7 4.9
5.1
Input Voltage (V)
I
DIODE
(mA)
V
DIODE
= 3.3V
V
DIODE
= 3.4V V
DIODE
= 3.5V
V
DIODE
= 3.6V
Efficiency vs. Input Voltage
(4x20mA)
50
55
60
65
70
75
80
85
90
95
100
2.7 2.9
3.1 3.3
3.5 3.7 3.9
4.1 4.3
4.5
4.7 4.9
5.1
Input Voltage (V)
Efficiency (%)
V
DIODE
= 3.3V
V
DIODE
= 3.4V
V
DIODE
= 3.5V
V
DIODE
= 3.6V
PDF 
ZIP