AAT3152
High Efficiency 1X/1.5X/2X Charge Pump
For White LED Applications
Preliminary Information
3152.2004.12.0.9
1
ChargePump
TM
General Description
The AAT3152 is a low noise, constant frequency
charge pump DC/DC converter that uses a tri-mode
load switch (1X), fractional (1.5X), and doubling (2X)
conversion to maximize efficiency for white LED
applications. The AAT3152 is capable of driving
four-channel LEDs from a 2.7V to 5.5V input. The
current sinks may be operated individually or in par-
allel for driving higher-current LEDs. Low external
parts count (two 1F flying capacitors and two small
1F capacitors at V
IN
and V
OUT
) makes this part ide-
ally suited for small battery-powered applications.
AnalogicTech's S
2
CwireTM (Simple Serial ControlTM)
serial digital input is used to enable, disable, and
set current for each LED with eight settings (20mA
down to 50A) including main/sub-display group
control. The AAT3152 consumes extremely low cur-
rent internally (80A typical) at light load for opti-
mized efficiency.
Each output of the AAT3152 is equipped with built-
in protection for V
OUT
short circuit and auto-disable
for load short-circuit condition. Built-in soft-start cir-
cuitry prevents excessive inrush current during
start-up. A low current shutdown feature discon-
nects the load from V
IN
and reduces quiescent cur-
rent to less than 1A.
The AAT3152 is available in a space-saving, ther-
mal-enhanced 12-pin 3x3mm DFN package.
Features
V
IN
Range: 2.7V to 5.5V
Fully Programmable Current with Single Wire
Eight-Step Current: 20mA to 50A
Individual Main-Sub Group Control
Low I
Q
(80A) at Light Load
Tri-Mode 1X, 1.5X, and 2X Charge Pump for
Maximum Efficiency and V
F
Coverage
Drives 1-4 Channels of LEDs
No Inductors, Low Noise Operation
1MHz Constant Switching Frequency
Small Application Circuit
Built-In Thermal Protection
Built-In Auto-Disable for Short-Circuit
Automatic Soft-Start
I
Q
<1A in Shutdown
Thermal-Enhanced 3x3mm12-Pin DFN
Package
Applications
Color (RGB) Lighting
Programmable Current Sinks
White LED Backlighting
White Photo Flash for DSCs
Typical Application
C1
1
F
C2
1
F
D1
D2
D3
D4
C
OUT
1
F
C
IN
1
F
2.7V to 5.5V
EN/SET
V
IN
EN/SET
C1+
C1-
C2+
C2-
V
OUT
D1
D2
D3
D4
GND
AAT3152
Pin Descriptions
Pin Configuration
DFN33-12
(TopView)
D4
EN/SET
C1+
1
C1-
VOUT
C2+
D3
D2
D1
GND
VIN
C2-
2
3
4
5
6
12
11
10
9
8
7
Pin #
Symbol
Function
1
D4
Current sink input #4.
2
EN/SET
S
2
Cwire serial interface control pin.
3
C1+
Flying capacitor 1 + terminal. Connect a 1F capacitor between C1+ and C1-.
4
C1-
Flying capacitor 1 - terminal.
5
OUTCP
Charge pump output to drive load circuit. Requires 1F capacitor connected
between this pin and ground.
6
C2+
Flying capacitor 2 + terminal. Connect a 1F capacitor between C2+ and C2-.
7
C2-
Flying capacitor 2 - terminal.
8
IN
Input power supply. Requires 1F capacitor connected between this pin and
ground.
9
GND
Ground.
10
D1
Current sink input #1.
11
D2
Current sink input #2.
12
D3
Current sink input #3.
EP
Exposed paddle (bottom); connect to GND directly beneath package.
AAT3152
High Efficiency 1X/1.5X/2X Charge Pump
For White LED Applications
2
3152.2004.12.0.9
Absolute Maximum Ratings
1
Notes:
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.
Thermal Information
Notes:
1. Mounted on an FR4 board.
2. Derate 20mW/C above 25C.
Symbol
Description
Value
Units
P
D
Maximum Power Dissipation
1, 2
2.0
W
JA
Maximum Thermal Resistance
1
50
C/W
Symbol
Description
Value
Units
V
IN
Input Voltage
-0.3 to 6
V
V
EN/SET
EN/SET to GND Voltage
-0.3 to V
IN
+ 0.3
V
I
OUT
2
Maximum DC Output Current
150
mA
T
J
Operating Junction Temperature Range
-40 to 150
C
T
LEAD
Maximum Soldering Temperature (at leads, 10 sec)
300
C
AAT3152
High Efficiency 1X/1.5X/2X Charge Pump
For White LED Applications
3152.2004.12.0.9
3
Electrical Characteristics1
C
IN
= C
OUT
= C1 = C2 = 1.0F; T
A
= -40C - 85C, unless otherwise noted.
Typical values are at T
A
= 25C, V
IN
= 3.6V.
Notes:
1. The AAT3152 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.
2. Current matching is defined as the deviation of any sink current from the average of all active channels.
Symbol
Description
Conditions
Min
Typ
Max Units
Input Power Supply
V
IN
Operation Range
2.7
5.5
V
1X Mode, 3.0
V
IN
5.5, Active,
0.3
1
No Load Current
1.5X Mode, 3.0
V
IN
5.5, Active,
1
3
mA
I
CC
Operating Current
No Load Current
2X Mode, 3.0
V
IN
5.5, Active,
1.5
3
No Load Current
50A Setting, 1X Mode
80
A
I
SHDN
Shutdown Current
EN/SET = 0
1
A
I
DX
I
SINK
Average Current Accuracy
I
SET
= 20mA, T
A
= 25C
-10
10
%
I
(D-Match)
Current Matching (Note 2)
V
F
:D1:D4 = 3.6V
12
%
V
TH
1X to 1.5X or 1.5X to 2X Transition
150
mV
Threshold at Any Current Sink Pin
Charge Pump Section
T
SS
Soft-Start Time
100
s
F
CLK
Clock Frequency
1000
kHz
EN/SET
V
EN(L)
Enable Threshold Low
0.4
V
V
EN(H)
Enable Threshold High
1.4
V
T
EN/SET LO
EN/SET Low Time
V
EN/SET
<0.6V
0.3
75
s
T
EN/SET HI
Minimum EN/SET High Time
V
EN/SET
>1.4V
50
ns
T
OFF
EN/SET Off Timeout
V
EN/SET
<0.6V
500
s
T
LAT
EN/SET Latch Timeout
V
EN/SET
>1.4V
500
s
I
EN/SET
EN/SET Input Leakage
-1
1
A
AAT3152
High Efficiency 1X/1.5X/2X Charge Pump
For White LED Applications
4
3152.2004.12.0.9
Typical Characteristics
Turn Off from 1.5X Mode
(V
IN
= 3.5V; 20mA Load)
200
s/div
EN
(2V/div)
I
IN
(100mA/div)
V
F
(1V/div)
Turn On to 2X Mode
(V
IN
= 2.8V; 20mA Load)
200
s/div
EN
(2V/div)
CP
(2V/div)
I
IN
(200mA/div)
V
SINK
(500mV/div)
Turn On to 1.5X Mode
(V
IN
= 3.5V; 20mA Load)
200
s/div
EN
(2V/div)
CP
(2V/div)
I
IN
(200mA/div)
V
SINK
(500mV/div)
Turn On to 1X Mode
(V
IN
= 4.2V; 20mA Load)
200
s/div
EN
(2V/div)
CP
(2V/div)
I
IN
(200mA/div)
V
SINK
(500mV/div)
Efficiency vs. Supply Voltage
Supply Voltage (V)
Efficiency (%)
50
60
70
80
90
100
2.8
3.0
3.2
3.4
3.6
3.8
4.0
4.2
10mA
20mA
AAT3152
High Efficiency 1X/1.5X/2X Charge Pump
For White LED Applications
3152.2004.12.0.9
5
PDF 
ZIP