AAT3112
500mA High Efficiency Charge Pump
for White LED Flash Applications
Typical Application
AAT3112
C1
+
C1
-
C2
+
C2
-
C1 = 1
F
C2 = 1
F
EN1
EN2
Enable Light
Enable Flash
D1
D2
D3
D4
V
OUT1
V
IN
V
OUT2
C
OUT
R
B
GND
C
IN
V
IN
3112.2004.12.1.2
1
ChargePump
TM
General Description
The AAT3112 is a member of AnalogicTech's Total
Power Management ICTM (TPMICTM) family. It is a
dual voltage doubling charge pump that provides a
regulated output voltage. It operates with an input
voltage range of 2.7 to 5.0 volts. The device can
deliver a constant 200mA output load current and up
to 500mA of pulsed current. The 500mA peak cur-
rent capability of the AAT3112 makes it ideal for
white LED flash applications. A low external parts
count (two 1F flying capacitors and two small
capacitors at V
IN
and V
OUT
) makes the AAT3112 ide-
ally suited for small battery-powered applications.
The AAT3112 has a thermal management system
to protect the device in the event of a short-circuit
condition at the output pin. Built-in soft-start circuit-
ry 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 quiescent current to less
than 1A. The AAT3112 is available in a 16-pin
3x3mm QFN package and is rated over the -40C
to +85C temperature range.
Features
Input Voltage Range:
AAT3112-5.0: 2.7V to 5.0V
AAT3112-4.5: 2.7V to 4.5V
Up to 500mA Peak Output Current
200mA Continuous Output Current
I
Q
<1A in Shutdown
Regulated 4.5V or 5.0V Output
26A of Quiescent Current
Small Application Circuit
Automatic Soft Start
No Inductors
Short-Circuit/Over-Temperature Protection
16-Pin 3x3mm QFN Package
Temperature Range: -40C to +85C
Applications
General-Purpose High-Current Boost Supply
White LED Backlighting
White LED Photo Flash
Pin Descriptions
Pin Configuration
QFN33-16
(Top View)
V
OUT1
V
IN
GND
V
OUT2
N/C
C2+
C2-
1
2
3
4
GND
V
IN
EN2
16
15
14
13
5
6
7
8
12
11
10
9
N/C
EN1
N/C
C1+
C1-
N/C
Pin #
Symbol
Function
1
N/C
No connect.
2
C2+
Flying capacitor 2 positive terminal. Connect 1F capacitor between C2+ and C2-.
3
C2-
Flying capacitor 2 negative terminal.
4
N/C
No connect.
5
V
IN
Input voltage. Connect to Pin 11.
6
GND
Ground connection.
7
EN2
Enable pin. When connected high, Charge Pump 2 is enabled. When connected low, it
disables the charge pump.
8
N/C
No connect.
9
EN1
Enable pin. When connected high, Charge Pump 1 is enabled. When connected low, it
disables the charge pump.
10
GND
Ground connection.
11
V
IN
Input voltage. Connect to Pin 5.
12
V
OUT1
Output pin for regulated output voltage. Bypass this pin to ground with a low ESR 10F
capacitor.
13
N/C
No connect.
14
C1+
Flying capacitor 1 positive terminal. Connect 1F capacitor between C1+ and C1-.
15
C1-
Flying capacitor 1 negative terminal.
16
V
OUT2
Regulated output voltage 2. Must be connected to V
OUT1
for higher current applications.
If used separately, bypass this pin to ground with a low ESR 10F capacitor.
EP
Exposed paddle (bottom); connect to GND directly beneath package.
AAT3112
500mA High Efficiency Charge Pump
for White LED Flash Applications
2
3112.2004.12.1.2
Absolute Maximum Ratings
1
Note 1: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at con-
ditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
Thermal Information
Note 1: Mounted on an FR4 board.
Symbol
Description
Value
Units
P
D
Maximum Power Dissipation
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
OUT
Charge Pump Output
-0.3 to 6
V
V
EN
EN to GND Voltage
-0.3 to 6
V
T
J
Operating Junction Temperature Range
-40 to 150
C
T
LEAD
Maximum Soldering Temperature (at leads, 10 sec)
300
C
AAT3112
500mA High Efficiency Charge Pump
for White LED Flash Applications
3112.2004.12.1.2
3
Electrical Characteristics
V
IN
= 3.3V, V
OUT
= 5.0V, C
IN
= C
OUT
= 10 F, C1 = C2 = 1.0F; T
A
= -40C to 85C, unless otherwise noted.
Typical values are T
A
= 25C.
Notes:
1. The AAT3112 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. V
OUT1
and V
OUT2
are pulled high to prevent switching.
Symbol
Description
Conditions
Min
Typ Max Units
AAT3112-4.5
Input Power Supply
V
IN
Operation Range
2.7
4.5
V
I
Q
Quiescent Current
2
2.7
V
IN
4.5, I
OUT
= 0 mA; EN1 = EN2 = V
IN
26
60
A
I
SHDN
Shutdown Current
EN1 = EN2 = 0
1.0
A
I
OUT
Pulsed Output Current
V
IN
= 3.6V; V
OUT
= 4.0V; T
PULSE
= 50mS
590
mA
V
IN
= 3.6V; V
OUT
=4.0V; T
PULSE
= 500mS
500
V
OUT
Output Voltage
2.7
V
IN
4.5, I
OUT
= 100mA
4.32
4.5
4.68
V
3.0
V
IN
4.5, I
OUT
= 200mA
4.32
4.5
4.68
Charge Pump Section
F
CLK
Clock Frequency
750
KHz
CP
Charge Pump Efficiency V
IN
= 2.7V; I
OUT
= 100mA
80
%
EN
V
EN(L)
Enable Threshold Low
0.3
V
V
EN(H)
Enable Threshold High
1.4
V
I
EN
EN Input Leakage
-1.0
1.0
A
AAT3112-5.0
Input Power Supply
V
IN
Operation Range
2.7
5.0
V
I
Q
Quiescent Current
2
2.7
V
IN
5.0, I
OUT
= 0 mA; EN1 = EN2 = V
IN
26
60
A
I
SHDN
Shutdown Current
EN1 = EN2 = 0
1.0
A
I
OUT
Pulsed Output Current
V
IN
= 3.6V; V
OUT
= 4.5V; T
PULSE
= 50mS
600
mA
V
IN
= 3.6V; V
OUT
=4.5V; T
PULSE
= 500mS
500
V
OUT
Output Voltage
2.7
V
IN
5.0, I
OUT
= 100mA
4.8
5.0
5.2
V
3.0
V
IN
5.0, I
OUT
= 200mA
4.8
5.0
5.2
Charge Pump Section
F
CLK
Clock Frequency
750
KHz
CP
Charge Pump Efficiency V
IN
= 2.7V; I
OUT
= 100mA
85
%
EN
V
EN(L)
Enable Threshold Low
0.3
V
V
EN(H)
Enable Threshold High
1.4
V
I
EN
EN Input Leakage
-1.0
1.0
A
AAT3112
500mA High Efficiency Charge Pump
for White LED Flash Applications
4
3112.2004.12.1.2
AAT3112
500mA High Efficiency Charge Pump
for White LED Flash Applications
3112.2004.12.1.2
5
Typical Characteristics
V
IN
=3.5V, C
IN
=C
OUT
=10F, C1=C2=1F, T
A
=25C, unless otherwise noted.
V
SHDN
Threshold vs. Supply Voltage
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
V
SHDN
Thr
e
s
hol
d (
V
)
V
IH
V
IL
V
IN
vs. V
IL
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
V
IL
(V)
-40
C
85
C
25
C
V
IN
vs. V
IH
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
V
IH
(V)
85
C
25
C
-40
C
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