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Электронный компонент: AAT3174

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General Description
The AAT3174 is a high output current, high effi-
ciency, low noise, low profile charge pump DC/DC
converter. The device is ideal for multi-functional
LED photo-flash applications where solution cost,
size, and efficiency are critical.
The AAT3174 is capable of driving a regulated out-
put current up to 800mA. Output current levels can
be easily programmed in 16 steps through
AnalogicTech's Simple Serial ControlTM (S
2
CwireTM)
interface controlled by a single microcontroller
GPIO line. This allows smooth transitions and flexi-
ble adjustment of brightness in flash or other light-
ing modes. The maximum output current can also
be set with an external R
SET
resistor.
The tri-mode (1X/1.5X/2X) operation of the internal
charge pump offers excellent power efficiency
throughout the output current range for both flash
and movie modes. Combined with a low external
parts count (two 1F flying capacitors and two
small bypass capacitors at V
IN
and OUT), the
AAT3174 is ideally suited for small battery-pow-
ered applications.
The AAT3174 has a thermal management system to
protect the device in the event of a short-circuit con-
dition at the output pin. Built-in soft-start circuitry pre-
vents excessive inrush current during start-up. The
shutdown feature disconnects the load from V
IN
and
reduces quiescent current to less than 1A.
The AAT3174 is available in a Pb-free, thermally-
enhanced 12-pin 3x3mm TDFN package and is spec-
ified over the -40C to +85C temperature range.
Features
Up to 800mA Output Current
Tri-Mode 1X/1.5X/2X in Current Mode
16 Current Steps Set by S
2
Cwire
External R
SET
to Set Maximum Current
<1A of Shutdown
Small Application Circuit
No Inductors
Automatic Soft Start
12-Pin TDFN 3x3mm Package
-40C to +85C Temperature Range
Applications
Camcorders
Camera Phones
Digital Still Cameras
PDAs and Notebook PCs
Smart Phones
AAT3174
High Current, High Efficiency Charge Pump
Typical Application
AAT3174
C1
1F
C2
1F
C
OUT
2.2F
C
IN
4.7F
EN/SET
VIN
C1+
C1- C2+
C2-
OUT
FL
V
IN
(2.7V to 5.5V)
Enable or
S
2
Cwire
Flash
LED
GND
RSET
3174.2006.04.1.1
1
ChargePump
TM
Pin Descriptions
Pin Configuration
TDFN33-12
(Top View)
VIN
C1+
C1-
1
GND
FL
RSET
VIN
OUT
C2+
C2-
N/C
EN/SET
2
3
4
5
6
12
11
10
9
8
7
Pin #
Symbol
Function
1
VIN
Input power supply pin. Requires 4.7F bypass capacitor to ground.
2
C1+
Flying capacitor C1 positive terminal. Connect a 1F capacitor between C1+ and C1-.
3
C1-
Flying capacitor C1 negative terminal.
4
GND
Ground connection.
5
FL
Controlled current sink. Connect the flash LED cathode to this pin.
6
RSET
Connect resistor here to set maximum output current.
7
EN/SET
Charge pump enable / set input control pin. When in the low state, the AAT3174 is
powered down and consumes less than 1A. When connected to logic high level,
the AAT3174 charge pump is active. This pin should not be left floating.
8
N/C
Not connected.
9
C2-
Flying capacitor C2 negative terminal.
10
C2+
Flying capacitor C2 positive terminal. Connect a 1F capacitor between C2+ and C2-.
11
OUT
Charge pump output. Requires 2.2F bypass capacitor to ground. Connect to flash LED
anode to drive the LED.
12
VIN
Input power supply pin. Requires 4.7F bypass capacitor to ground.
EP
Exposed paddle (bottom). Connect to GND directly beneath package.
AAT3174
High Current, High Efficiency Charge Pump
2
3174.2006.04.1.1
Absolute Maximum Ratings
1
T
A
= 25C, unless otherwise noted.
Thermal Information
2
Symbol
Description
Value
Units
JA
Thermal Resistance
50
C/W
P
D
Maximum Power Dissipation
2.0
mW
Symbol
Description
Value
Units
V
IN
Input Voltage
-0.3 to 6.0
V
V
EN
EN to GND Voltage
-0.3 to 6.0
V
V
EN(MAX)
Maximum EN to Input Voltage
V
IN
+ 0.3
V
I
OUT
Maximum Output Current
1000
mA
T
J
Operating Temperature Range
-40 to 150
C
T
S
Storage Temperature Range
-65 to 150
C
T
LEAD
Maximum Soldering Temperature (at leads, 10 sec)
300
C
AAT3174
High Current, High Efficiency Charge Pump
3174.2006.04.1.1
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. Mounted on an FR4 board.
Electrical Characteristics
1
C
IN
= 4.7F, C
OUT
= 2.2F, 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
Power Supply
V
IN
Input Voltage Range
2.7
5.5
V
1X, No Load Current
300
A
3.0
V
IN
5.5, 1.5X Mode,
2.0
4.0
I
CC
Operating Current
No Load Current
mA
3.0
V
IN
5.5, 2X Mode,
3.0
6.0
No Load Current
I
SHDN(MAX)
V
IN
Pin Shutdown Current
EN = 0
1.0
A
I
OUT(MAX)
2
Maximum Output Current
V
F
= 3.6V
800
mA
I
DX
Output Current Accuracy
Programmed for 600mA;
540
660
mA
R
SET
= 187k
T
SS
Soft-Start Time
200
s
V
RSET
R
SET
Pin Voltage
0.7
V
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
60
s
T
EN/SET HI
Minimum EN/SET High Time
50
ns
T
EN/SET HI MAX
Maximum EN/SET High Time
60
s
T
OFF
EN/SET Off Timeout
500
s
T
LAT
EN/SET Latch Timeout
500
s
Input Current
EN/SET Input Leakage
-1
1
A
AAT3174
High Current, High Efficiency Charge Pump
4
3174.2006.04.1.1
1. The AAT3174 is guaranteed to meet performance specifications from 0C to 70C. Specification over the -40C to +85C operating
temperature range is assured by design, characterization, and correlation with statistical process controls.
2. Mounted on an FR4 board.
Typical Characteristics
V
IN
= 3.6V, C
IN
= 4.7F, C
OUT
= 2.2F, C
1
= C
2
= 1F, T
A
= 25C, unless otherwise noted.
Turn-Off from 1.5X Mode
(V
IN
= 3.2V; I
LED
= 150mA)
Time (200s/div)
EN
(2V/div)
I
IN
(200mA/div)
V
F
(1V/div)
Turn-On to 2X Mode
(V
IN
= 3.2V; I
LED
= 600mA)
Time (200s/div)
EN
(2V/div)
V
OUT
(2V/div)
I
IN
(500mA/div)
V
SINK
(1V/div)
Turn-On to 1X Mode
(V
IN
= 4.2V; I
LED
= 600mA)
Time (200s/div)
EN
(2V/div)
V
OUT
(2V/div)
I
IN
(500mA/div)
V
SINK
(1V/div)
Turn-On to 1.5X Mode
(V
IN
= 3.2V; I
LED
= 150mA)
Time (200s/div)
EN
(2V/div)
V
OUT
(2V/div)
I
IN
(200mA/div)
V
SINK
(1V/div)
Turn-On to 1X Mode
(V
IN
= 4.2V; I
LED
= 150mA)
Time (200s/div)
EN
(2V/div)
V
OUT
(2V/div)
I
IN
(200mA/div)
V
SINK
(1V/div)
Efficiency vs. Supply Voltage
Supply Voltage (V)
Efficiency (%)
0
10
20
30
40
50
60
70
80
90
100
2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2
I
LED
= 300mA
I
LED
= 150mA
AAT3174
High Current, High Efficiency Charge Pump
3174.2006.04.1.1
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