General Description
The AAT3167 is a low noise, constant frequency
charge pump DC/DC converter that uses a tri-
mode load switch (1X), fractional (1.5X), and dou-
bling (2X) conversion to maximize efficiency for
white LED applications. The AAT3167 is capable of
driving five LEDs for a total of 135mA from a 2.7V
to 5.5V input. The current sinks may be operated
individually or in parallel for driving higher current
LEDs. A low external parts count (two 1F flying
capacitors and two small 1F capacitors at IN and
OUTCP) make this part ideally suited for small,
battery-powered applications.
AnalogicTech's AS
2
CwireTM (Advanced Simple
Serial ControlTM) serial digital input is used to
enable, disable, and set current for each LED with
a 16-level logarithmic scale plus four low-current
settings down to 115A. For optimized efficiency,
low-current settings require only 50A of house-
keeping current.
Each output of the AAT3167 is equipped with built-
in protection for output short circuit and auto-dis-
able for load short-circuit conditions. Built-in soft-
start circuitry prevents excessive inrush current
during start-up. A low-current shutdown feature dis-
connects the load from the input and reduces qui-
escent current to less than 1A.
The AAT3167 is available in a Pb-free, space-sav-
ing, thermally-enhanced, 16-pin 3x4mm TDFN or
16-pin 4x4mm QFN package and is rated over the
-40C to +85C temperature range.
Features
V
IN
Range: 2.7V to 5.5V
Fully Programmable Current with Single Wire
-- 16-Step Logarithmic Scale
-- 14/18/27mA Max Current
-- Four Low-Current Settings Down to 115A
-- Low I
Q
(50A) for Single-Channel, Low-
Current Mode
Tri-Mode 1X, 1.5X, 2X Charge Pump for
Maximum Efficiency and V
F
Coverage
Drives Up to Five LEDs
Individual Main-Sub (4-1) Group Control
No Inductors, Low Noise Operation
1MHz Constant Switching Frequency
Small Application Circuit
Built-In Thermal Protection
Built-In Auto-Disable for Open Circuit
Automatic Soft Start
I
Q
<1A in Shutdown
TDFN34-16 or QFN44-16 Package
Applications
Color (RGB) Lighting
Programmable Current Sink
Transmissive LCD Display
White LED Backlighting
White Photo Flash for Digital Still Cameras
AAT3167
High Efficiency 1X/1.5X/2X Charge
Pump for White LED Applications
Typical Application
C1
1F
C2
1F
D1
D2
D3
D4
D5
C
OUT
1F
C
IN
1F
2.7V to 5.5V
EN/SET
IN
EN/SET
C1+
C1-
C2+
C2-
OUTCP
D1
D2
D3
D4
D5
GND
AAT3167
3167.2006.05.1.3
1
ChargePump
TM
Pin Descriptions
Pin Configuration
TDFN34-16
QFN44-16
(Top View)
(Top View)
1
2
3
4
12
11
10
9
5
6
7
8
16
15
14
13
N/C
EN/SET
N/C
OUTCP
C2+
C1+
C1-
C2-
GND
IN
GND
D1
D2
D3
D4
D5
N/C
OUTCP
C2+
N/C
EN/SET
3
C1+
C1-
C2-
D3
D2
D1
D5
D4
GND
IN
GND
4
5
1
2
6
7
8
14
13
12
16
15
11
10
9
Pin #
Symbol
Function
1, 3
N/C
No connection.
2
EN/SET
AS
2
Cwire serial interface control pin.
4
OUTCP
Charge pump output to drive load circuit. Requires 1F capacitor connected between this
pin and ground.
5
C2+
Flying capacitor 2 positive terminal. Connect a 1F capacitor between C2+ and C2-.
6
C1+
Flying capacitor 1 positive terminal. Connect a 1F capacitor between C1+ and C1-.
7
C1-
Flying capacitor 1 negative terminal.
8
C2-
Flying capacitor 2 negative terminal.
9, 11
GND
Ground.
10
IN
Input power supply. Requires 1F capacitor connected between this pin and ground.
12
D1
Current sink input #1.
13
D2
Current sink input #2.
14
D3
Current sink input #3.
15
D4
Current sink input #4.
16
D5
Current sink input #5.
EP
Exposed paddle (bottom); connect to ground as closely as possible to the package.
AAT3167
High Efficiency 1X/1.5X/2X Charge
Pump for White LED Applications
2
3167.2006.05.1.3
Absolute Maximum Ratings
1
Thermal Information
3
Symbol
Description
Value
Units
P
D
Maximum Power Dissipation
QFN44-16
4
2.0
W
TDFN34-16
4
JA
Maximum Thermal Resistance
QFN44-16
50
C/W
TDFN34-16
Symbol
Description
Value
Units
V
IN
Input Voltage to GND
-0.3 to 6
V
V
EN/SET
EN/SET Voltage to GND
-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
AAT3167
High Efficiency 1X/1.5X/2X Charge
Pump for White LED Applications
3167.2006.05.1.3
3
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. Based on long-term current density limitation.
3. Mounted on an FR4 board.
4. Derate 20mW/C above 25C.
Electrical Characteristics
1
C
IN
= C
OUT
= C
1
= C
2
= 1.0F; T
A
= -40C to +85C, unless otherwise noted. Typical values are T
A
= 25C,
V
IN
= 3.6V.
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,
No Load Current, High Current Mode
0.3
1.5X Mode, 3.0
V
IN
5.5, Active,
I
CC
Operating Current
No Load Current, High Current Mode
1
mA
2X Mode, 3.0
V
IN
5.5, Active,
No Load Current, High Current Mode
1
1X Mode, 3.0
V
IN
5.5, D5 Active,
I
DS
= 100A, Low Current Mode
50
A
I
SHDN
Shutdown Current
V
EN/SET
= 0V
1
A
I
DX
High Current Accuracy
I
SET
= 18mA, T
A
= 25C
-10
10
%
Low Current Accuracy
I
SET
= 400A, T
A
= 25C
15
%
I
(D-Match)
Current Matching
2
V
F
:D1:D5 = 3.6V
0.5
1
%
V
TH
1X to 1.5X or 1.5X to 2X Transition
150
mV
Threshold at Any I
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
V
IN
= 2.7V
0.4
V
V
EN(H)
Enable Threshold High
V
IN
= 5.5V
1.4
V
T
EN/SET LO
EN/SET Low Time
0.3
75
s
T
EN/SET HI
Minimum EN/SET High Time
50
ns
T
EN/SET HI MAX
Maximum EN/SET High Time
75
s
T
OFF
EN/SET Off Timeout
500
s
T
LAT
EN/SET Latch Timeout
500
s
I
EN/SET
EN/SET Input Leakage
-1
1
A
AAT3167
High Efficiency 1X/1.5X/2X Charge
Pump for White LED Applications
4
3167.2006.05.1.3
1. The AAT3167 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.
Typical Characteristics
C
IN
= C
OUT
= C
1
= C
2
= 1.0F; T
A
= 25C, V
IN
= 3.6V, unless otherwise noted.
Current Matching vs. Temperature
Temperature (
C)
Current (mA)
17.0
17.2
17.4
17.6
17.8
18.0
18.2
18.4
18.6
18.8
19.0
-40
-20
0
20
40
60
80
Channel 1
Channel 4
Channel 2
Channel 3
Channel 5
Turn-Off from 1.5X Mode
(V
IN
= 3.5V; 18mA Load)
100
s/div
EN
(2V/div)
I
IN
(100mA/div)
V
F
(1V/div)
Turn-On to 2X Mode
(V
IN
= 2.8V; 18mA Load)
100
s/div
EN
(2V/div)
OUT
(2V/div)
I
IN
(200mA/div)
V
SINK
(500mV/div)
Turn-On to 1.5X Mode
(V
IN
= 3.5V; 18mA Load)
100
s/div
EN
(2V/div)
OUT
(2V/div)
I
IN
(200mA/div)
V
SINK
(500mV/div)
Turn-On to 1X Mode
(V
IN
= 4.2V; 18mA Load)
100
s/div
EN
(2V/div)
OUT
(2V/div)
I
IN
(200mA/div)
V
SINK
(500mV/div)
Efficiency vs. Supply Voltage
Supply Voltage (V)
Efficiency (%)
0
10
20
30
40
50
60
70
80
90
100
2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5
18mA
V
F
= 3.4V
5.1mA
V
F
= 3.0V
350A
V
F
= 2.7V
AAT3167
High Efficiency 1X/1.5X/2X Charge
Pump for White LED Applications
3167.2006.05.1.3
5
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