202100A.pdf

DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
General Description
Features
The AAT3174 is a high output current, high efficiency,
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.
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The AAT3174 is capable of driving a regulated output
current up to 800mA. Output current levels can be easily programmed in 16 steps through Skyworks’ Simple
Serial Control™ (S2Cwire™) interface controlled by a
single microcontroller GPIO line. This allows smooth
transitions and flexible adjustment of brightness in flash
or other lighting modes. The maximum output current
can also be set with an external RSET resistor.
Up to 800mA Output Current
Tri-Mode 1X/1.5X/2X in Current Mode
16 Current Steps Set by S2Cwire
External RSET to Set Maximum Current
<1μA of Shutdown
Small Application Circuit
No Inductors
Automatic Soft Start
12-Pin TDFN 3x3mm Package
-40°C to +85°C Temperature Range
Applications
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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
1μF flying capacitors and two small bypass capacitors at
VIN and OUT), the AAT3174 is ideally suited for small
battery-powered applications.
Camcorders
Camera Phones
Digital Still Cameras
PDAs and Notebook PCs
Smart Phones
The AAT3174 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 circuitry prevents
excessive inrush current during start-up. The shutdown
feature disconnects the load from VIN and reduces quiescent current to less than 1μA.
The AAT3174 is available in a Pb-free, thermally-enhanced
12-pin 3x3mm TDFN package and is specified over the
-40°C to +85°C temperature range.
Typical Application
C1
1μF
C1+
VIN
(2.7V to 5.5V)
Enable or
S2Cwire
C2
1μF
C1- C2+
VIN
C2OUT
AAT3174
C IN
4.7μF
EN/SET
COUT
2.2μF
Flash
LED
FL
RSET
GND
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
1
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Pin Descriptions
Pin #
Symbol
1
2
3
4
5
6
VIN
C1+
C1GND
FL
RSET
7
EN/SET
8
9
10
N/C
C2C2+
11
OUT
12
EP
VIN
Function
Input power supply pin. Requires 4.7μF bypass capacitor to ground.
Flying capacitor C1 positive terminal. Connect a 1μF capacitor between C1+ and C1-.
Flying capacitor C1 negative terminal.
Ground connection.
Controlled current sink. Connect the flash LED cathode to this pin.
Connect resistor here to set maximum output current.
Charge pump enable / set input control pin. When in the low state, the AAT3174 is powered down and
consumes less than 1μA. When connected to logic high level, the AAT3174 charge pump is active. This
pin should not be left floating.
Not connected.
Flying capacitor C2 negative terminal.
Flying capacitor C2 positive terminal. Connect a 1μF capacitor between C2+ and C2-.
Charge pump output. Requires 2.2μF bypass capacitor to ground. Connect to flash LED anode to drive
the LED.
Input power supply pin. Requires 4.7μF bypass capacitor to ground.
Exposed paddle (bottom). Connect to GND directly beneath package.
Pin Configuration
TDFN33-12
(Top View)
VIN
C1+
C1GND
FL
RSET
2
1
12
2
11
3
10
4
9
5
8
6
7
VIN
OUT
C2+
C2N/C
EN/SET
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Absolute Maximum Ratings1
TA = 25°C, unless otherwise noted.
Symbol
VIN
VEN
VEN(MAX)
IOUT
TJ
TS
TLEAD
Description
Input Voltage
EN to GND Voltage
Maximum EN to Input Voltage
Maximum Output Current
Operating Temperature Range
Storage Temperature Range
Maximum Soldering Temperature (at leads, 10 sec.)
Value
Units
-0.3 to 6.0
-0.3 to 6.0
VIN + 0.3
1000
-40 to 150
-65 to 150
300
V
V
V
mA
°C
°C
°C
Value
Units
50
2.0
°C/W
mW
Thermal Information2
Symbol
JA
PD
Description
Thermal Resistance
Maximum Power Dissipation
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. Mounted on an FR4 board.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
3
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Electrical Characteristics1
CIN = 4.7μF, COUT = 2.2μF, C1 = C2 = 1.0μF; TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C,
VIN = 3.6V.
Symbol
Description
Conditions
Power Supply
Input Voltage Range
VIN
ICC
Operating Current
ISHDN(MAX)
IOUT(MAX)2
IDX
TSS
VRSET
EN/SET
VEN(L)
VEN(H)
TEN/SET LO
TEN/SET HI
TEN/SET HI MAX
TOFF
TLAT
Input Current
VIN Pin Shutdown Current
Maximum Output Current
Output Current Accuracy
Soft-Start Time
RSET Pin Voltage
Enable Threshold Low
Enable Threshold High
EN/SET Low Time
Minimum EN/SET High Time
Maximum EN/SET High Time
EN/SET Off Timeout
EN/SET Latch Timeout
EN/SET Input Leakage
Min
Typ
2.7
1X, No Load Current
3.0 ≤ VIN ≤ 5.5, 1.5X Mode, No Load Current
3.0 ≤ VIN ≤ 5.5, 2X Mode, No Load Current
EN = 0
VF = 3.6V
Programmed for 600mA; RSET = 187k
300
2.0
3.0
Max
Units
5.5
V
4.0
6.0
1.0
μA
800
540
660
200
0.7
VIN = 2.7V
VIN = 5.5V
0.4
1.4
0.3
60
50
-1
60
500
500
1
μA
mA
mA
μs
V
V
V
μs
ns
μs
μs
μs
μA
1. The AAT3174 is guaranteed to meet performance specifications from 0°C to 70°C. Specification over the -40°C to +85°C operating temperature range is assured by design,
characterization, and correlation with statistical process controls.
2. Mounted on an FR4 board.
4
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Typical Characteristics
VIN = 3.6V, CIN = 4.7μF, COUT = 2.2μF, C1 = C2 = 1μF, TA = 25°C, unless otherwise noted.
Efficiency vs. Supply Voltage
Turn-On to 1X Mode
(VIN = 4.2V; ILED = 150mA)
100
90
EN
(2V/div)
Efficiency (%)
80
70
ILED = 300mA
60
ILED = 150mA
50
40
VSINK
(1V/div)
30
20
IIN
(200mA/div)
10
0
VOUT
(2V/div)
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
Time (200µs/div)
Supply Voltage (V)
Turn-On to 1.5X Mode
Turn-On to 1X Mode
(VIN = 3.2V; ILED = 150mA)
(VIN = 4.2V; ILED = 600mA)
EN
(2V/div)
EN
(2V/div)
VOUT
(2V/div)
VOUT
(2V/div)
VSINK
(1V/div)
VSINK
(1V/div)
IIN
(200mA/div)
IIN
(500mA/div)
Time (200µs/div)
Time (200µs/div)
Turn-On to 2X Mode
Turn-Off from 1.5X Mode
(VIN = 3.2V; ILED = 600mA)
(VIN = 3.2V; ILED = 150mA)
EN
(2V/div)
EN
(2V/div)
VOUT
(2V/div)
VF
(1V/div)
VSINK
(1V/div)
IIN
(200mA/div)
IIN
(500mA/div)
Time (200µs/div)
Time (200µs/div)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
5
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Typical Characteristics
VIN = 3.6V, CIN = 4.7μF, COUT = 2.2μF, C1 = C2 = 1μF, TA = 25°C, unless otherwise noted.
Operating Characteristic
Operating Characteristic
(VIN = 3.3V; 1.5X Mode; ILED = 300mA)
(VIN = 2.9V; 2X Mode; ILED = 300mA)
VIN
(100mV/div)
VIN
(100mV/div)
VOUT
(200mV/div)
VOUT
(200mV/div)
VSINK
(200mV/div)
VSINK
(200mV/div)
Time (2µs/div)
Time (2µs/div)
LED Current vs. RSET
TLAT vs. VIN
(Data = 1)
1000
160
900
140
800
120
TLAT (µs)
ILED (mA)
700
600
500
400
300
100
85°C
80
60
40
200
20
100
0
100
25°C
-40°C
0
200
300
400
500
600
700
800
900
1000
RSET (kΩ
Ω)
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 5.3 5.5
Input Voltage (V)
TOFF vs. VIN
180
160
TOFF (µs)
140
120
100
25°C
-40°C
85°C
80
60
40
20
0
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 5.3 5.5
Input Voltage (V)
6
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Typical Characteristics
VIN = 3.6V, CIN = 4.7μF, COUT = 2.2μF, C1 = C2 = 1μF, TA = 25°C, unless otherwise noted.
VIH vs. VIN Over Temperature
VIL vs. VIN Over Temperature
1.0
0.9
1.0
-40°C
0.9
0.7
0.6
0.8
25°C
85°C
0.5
VIL (V)
VIH (V)
0.8
-40°C
0.7
0.6
25°C
85°C
0.5
0.4
0.4
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 5.3 5.5
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 5.3 5.5
Input Voltage (V)
Input Voltage (V)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
7
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Functional Block Diagram
C1+
C1-
C2+
C2-
VIN
Charge Pump
Section 1
Charge Pump
Section 2
OUT
1MHz
Oscillator
Soft-Start
Control
FL
EN/SET
System Control;
S2Cwire;
Timing
RSET
GND
Functional Description
S2Cwire Serial Interface
The AAT3174 is a high efficiency, low noise, dual stage
tri-mode 1X/1.5X/2X charge pump device intended for
photo-flash LED applications. The device requires only
four external components: two ceramic capacitors for
the charge pump flying capacitors, one ceramic capacitor
for CIN, and one ceramic capacitor for COUT.
The AAT3174 utilizes Skyworks single wire S2Cwire interface to enable/disable the charge pump and adjust the
output current at 16 current levels. Each code defines the
output current to be a percentage of the maximum current set by the resistor at the RSET pin (see Table 1).
The charge pump is designed to deliver regulated load
currents up to 800mA. The dual stage charge pump section contains soft-start circuitry to prohibit excessive
inrush current during start-up. System efficiency is
maximized with a tri-mode, dual stage charge pump
topology. The internal clock oscillator at 1MHz allows the
use of small external components.
The tri-mode charge pump operation further optimizes
power conversion efficiency. Depending upon the variance of load current (at different modes), input voltage,
and nominal LED forward voltage, the charge pump will
operate in a 1X, 1.5X, or 2X mode to generate the output
voltage required to power the load for a given controlled
constant current. This results in significant power savings over voltage doubling architectures, especially when
the LEDs are also operated at lower current levels in
movie, viewing, or flashlight modes.
8
Data
Total Output (% of IMAX)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
100.0
89.1
79.4
70.8
63.1
56.2
50.1
44.7
39.8
35.5
31.6
28.2
25.1
22.4
20.0
0.0
Table 1: Current Level Settings.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
S2Cwire Serial Interface Timing
THI
TLO
TOFF
T LAT
EN/SET
1
2
n ≤ 16
n-1
0
Data Reg
n
0
Application Information
The S2Cwire interface records rising edges of the EN/SET
pin and decodes them into 16 individual current level
settings with Code 1 reserved for maximum current.
Once EN/SET has been held in the logic high state for
time TLAT, the programmed current is seen at the current
source outputs and the internal data register is reset to
0. For subsequent current level programming, the number of rising edges corresponding to the desired code
must be entered on the EN/SET pin.
Flash/Torch Control Using the RSET Pin
An alternative method can be used for flash/torch control that eliminates the need to use the S2Cwire singlewire interface. By using any typical digital I/O port, an
additional enable can be created (see Figure 1).
The I/O port output configuration can be any one of opendrain NMOS, open-drain PMOS, or push-pull type. The
control will always act as an active-low flash enable or,
equivalently, an active-high torch enable (see Table 2).
When EN/SET is held low for an amount of time greater
than TOFF, the AAT3174 enters into shutdown mode and
draws less than 1μA from VIN. Data and address registers are reset to 0 during shutdown.
EN
ENFL
Mode
0
0
1
1
0
1
0
1
Off
Off
Flash
Torch
Table 2: Flash/Torch Control Modes.
C1
1μF
C1+
2.7V
to 5.5V
C2
1μF
C1- C2+
VIN
CIN
4.7μF
EN
C2VOUT
COUT
2.2μF
AAT 3174
Flash
LED
F1
EN/SET
R2
RSET
ENFL
GND
R1
Figure 1: Flash/Torch Control Using the RSET Pin.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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9
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
According to I/O port type, the following equations can
be used to calculate appropriate resistor values.
For an open-drain NMOS I/O port output configuration,
the line is pulled low to GND or left floating, according to
state. To calculate the appropriate R1 and R2 resistor
values, first calculate the R1 resistor value needed for the
desired torch level LED current:
Next, choose R2 based on the desired flash level LED current:
R1 · 600mA · 187kΩ
R1 · ILED (flash) - 600mA · 187kΩ
For examples of standard 1% values where the LED flash
current level is targeted for 700mA, see Table 3.
R1
(kΩ)
R2
(kΩ)
ILED
Torch (mA)
ILED
Flash (mA)
920
732
649
562
193
205
210
223
122
153
173
200
703
701
707
703
Table 3: Open-Drain I/O Example Resistor Values.
If the I/O port must be configured as an open-drain PMOS
type output, the appropriate equations can be generated
from these same concepts. As done in the previous example, the necessary values can then be calculated.
As a reference, the equations applicable to the PMOS
case are:
600mA · 187kΩ
ILED (flash)
VIO
-1
0.7
R2 =
ILED (torch)
1
R1 600mA · 187kΩ
10
600mA · 187kΩ
ILED (flash)
Next, choose a reasonable value for R1. A value that is
slightly larger than RSET, calculated from above, is appropriate. Calculate R2 and then calculate the torch mode
current level that results:
R2 =
The current and resistance values used in the equations
come from the conditions placed on the IDX parameter of
the Electrical Characteristics table.
R1 =
For a push-pull I/O port output configuration, first calculate the overall RSET value needed for the desired flash
level LED current:
RSET =
600mA · 187kΩ
R1 =
ILED (torch)
R2 =
The value to use for VIO must come from the I/O supply
voltage used in the system. 0.7V is the typical value of
the VRSET parameter found in the Electrical Characteristics.
RSET · R1
R1 - RSET
ILED (torch) = 600mA · 187kΩ ·
VIO ⎞
⎛ R2 - R1
⎝ R1 · R2 0.7V · R2 ⎠
Once again, the current and resistance values used in
the equations come from the conditions placed on the IDX
parameter of the Electrical Characteristics table. 0.7V is
the typical value for the VRSET parameter. The value to
use for VIO must come from the I/O supply voltage used
in the system.
Example standard 1% values are provided in Table 4.
R1
(kΩ)
R2
(kΩ)
ILED
Torch (mA)
ILED
Flash (mA)
169
165
162
160
1000
1000
1000
1000
95
111
124
132
776
792
805
813
Table 4: Push-Pull I/O Example Resistor Values.
In all of the approaches mentioned, the open-drain
NMOS or PMOS type configurations offer the most flexibility for current level selection.
When configured as an output, if the I/O port is only
push-pull type, then the equivalent open-drain NMOS
can also be realized. To realize this, activate the port as
output only when driving the line low. Otherwise, to
release the line, set the port to be tri-stated.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Device Power Efficiency
LED Selection
The AAT3174 power conversion efficiency depends on
the charge pump mode. By definition, device efficiency
is expressed as the output power delivered to the LED
divided by the total input power consumed.
The AAT3174 is designed to drive high-intensity white
LEDs. It is particularly suitable for LEDs with an operating forward voltage in the range of 4.2V to 1.5V.
η=
POUT
PIN
When the input voltage is sufficiently greater than the
LED forward voltage, the device optimizes efficiency by
operating in 1X mode. In 1X mode, the device is working
as a bypass switch and passing the input supply directly
to the output. The power conversion efficiency can be
approximated by,
η=
VF · ILED VF
≈
VIN · IIN
VIN
Due to the very low 1X mode quiescent current, the
input current nearly equals the current delivered to the
LED. Further, the low-impedance bypass switch introduces negligible voltage drop from input to output.
The AAT3174 further maintains optimized performance
and efficiency by detecting when the input voltage is not
sufficient to sustain LED current. The device automatically switches to 1.5X mode when the input voltage
drops too low in relation to the LED forward voltage.
In 1.5X mode, the output voltage can be boosted to 3/2
the input voltage. The 3/2 conversion ratio introduces a
corresponding 1/2 increase in input current. For ideal
conversion, the 1.5X mode efficiency is given by:
VF
VF · ILED
η=
=
VIN · 1.5IIN 1.5 · VIN
Similarly, when the input falls further, such that 1.5X
mode can no longer sustain LED current, the device will
automatically switch to 2X mode. In 2X mode, the output voltage can be boosted to twice the input voltage.
The doubling conversion ratio introduces a corresponding doubling of the input current. For ideal conversion,
the 2X mode efficiency is given by:
η=
VF
VF · ILED
=
VIN · 2IIN
2 · VIN
The charge pump device can also drive other loads that
have similar characteristics to white LEDs. For various
load types, the AAT3174 provides a high-current, programmable ideal constant current source.
Capacitor Selection
Careful selection of the four external capacitors CIN, C1,
C2, and COUT is important because they will affect turn-on
time, output ripple, and transient performance. Optimum
performance will be obtained when low equivalent series
resistance (ESR) ceramic capacitors are used. In general, low ESR may be defined as less than 100m. A
value of 1μF for the flying capacitors is a good starting
point when choosing capacitors. If the LED current sinks
are only programmed for light current levels, then the
capacitor size may be decreased.
Ceramic composition capacitors are highly recommended
over all other types of capacitors for use with the
AAT3174. Ceramic capacitors offer many advantages
over their tantalum and aluminum electrolytic counterparts. A ceramic capacitor typically has very low ESR, is
lowest cost, has a smaller PCB footprint, and is nonpolarized. Low ESR ceramic capacitors help maximize
charge pump transient response. Since ceramic capacitors are non-polarized, they are not prone to incorrect
connection damage.
Equivalent Series Resistance
ESR is an important characteristic to consider when
selecting a capacitor. ESR is a resistance internal to a
capacitor that is caused by the leads, internal connections, size or area, material composition, and ambient
temperature. Capacitor ESR is typically measured in
milliohms for ceramic capacitors and can range to more
than several ohms for tantalum or aluminum electrolytic
capacitors.
Ceramic Capacitor Materials
Ceramic capacitors less than 0.1μF are typically made
from NPO or C0G materials. NPO and C0G materials
generally have tight tolerance and are very stable over
temperature. Larger capacitor values are usually composed of X7R, X5R, Z5U, or Y5V dielectric materials.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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11
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Large ceramic capacitors are often available in lowercost dielectrics, but capacitors greater than 4.7μF are
not typically required for AAT3174 applications.
Capacitor area is another contributor to ESR. Capacitors
that are physically large will have a lower ESR when
compared to an equivalent material smaller capacitor.
These larger devices can improve circuit transient
response when compared to an equal value capacitor in
a smaller package size.
Thermal Protection
The AAT3174 has a thermal protection circuit that will
shut down the charge pump if the die temperature rises
above the thermal limit, as is the case during a shortcircuit of the OUT pin.
The PCB area directly underneath the package should be
plated so that the exposed paddle can be mated to the
top layer PCB copper during the re-flow process. This
area should also be connected to the top layer ground
pour when available. Further, multiple copper plated
thru-holes should be used to electrically and thermally
connect the top surface paddle area to additional ground
plane(s) and/or the bottom layer ground pour.
The chip ground is internally connected to both the paddle
and the GND pin. The GND pin conducts large currents
and it is important to minimize any differences in potential
that can result between the GND pin and exposed paddle.
It is good practice to connect the GND pin to the exposed
paddle area using a trace as shown in Figure 2.
PCB Layout
To achieve adequate electrical and thermal performance,
careful attention must be given to the PCB layout. In the
worst-case operating condition, the chip must dissipate
considerable power at full load. Adequate heat-sinking
must be achieved to ensure intended operation.
Figure 2 illustrates an example of an adequate PCB layout. The bottom of the package features an exposed
metal paddle. The exposed paddle acts, thermally, to
transfer heat from the chip and, electrically, as a ground
connection.
The junction-to-ambient thermal resistance (JA) for the
package can be significantly reduced by following a
couple of important PCB design guidelines.
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Figure 2: Example PCB Layout.
The flying capacitors C1 and C2 should be connected
close to the chip. Trace length should be kept short to
minimize path resistance and potential coupling. The
input and output capacitors should also be placed as
close to the chip as possible.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
TDFN33-12
RSXYY
AAT3174IWP-T1
Skyworks Green™ products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of Green™, document number
SQ04-0074.
Package Information
TDFN33-123
Index Area
0.43 ± 0.05
0.1 REF
C0.3
0.45 ± 0.05
2.40 ± 0.05
3.00 ± 0.05
Detail "A"
3.00 ± 0.05
1.70 ± 0.05
Top View
Bottom View
0.23 ± 0.05
Pin 1 Indicator
(optional)
0.05 ± 0.05
0.23 ± 0.05
0.75 ± 0.05
Detail "A"
Side View
All dimensions in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing
process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012
13
DATA SHEET
AAT3174
High Current, High Efficiency Charge Pump
Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved.
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14
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202100A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012