Data Sheets - Skyworks Solutions, Inc.

DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
General Description
Features
The AAT3134 is a low noise, constant frequency charge
pump DC/DC converter that uses a dual mode load
switch (1X) and fractional (1.5X) conversion to maximize
efficiency for white LED applications. The device can be
used to produce current levels up to 20mA in each of its
six outputs to drive LEDs from a 2.7V to 5.5V input.
Outputs may be operated individually or paralleled for
driving higher-current LEDs. A low external parts count
(two 1µF flying capacitors and two small 1µF capacitors
at VIN and OUT) make the AAT3134 ideally suited for
small battery-powered applications.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Skyworks' Simple Serial Control™ (S2Cwire™) interface
is used to enable, disable, and set the LED drive current
in two groups of four outputs and two outputs with
multiple-level, independently-controlled brightness
scales. The AAT3134 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. A high
charge pump switching frequency enables the use of
very small external capacitors. A low-current shutdown
feature disconnects the load from VIN and reduces quiescent current to less than 1µA. The AAT3134 is available
in a Pb-free 16-pin QFN44 package and is rated over the
-40°C to +85°C temperature range.
VIN Range: 2.7V to 5.5V
<1.0µA of Shutdown
1MHz Switching Frequency
Fully Independent Display Lighting
Dual Mode 1X and 1.5X Charge Pump for Maximum
Efficiency
Drives Low-VF and High-VF Type LEDs
Up to Six 20mA Outputs
Multi-Position Brightness Scale with Digital Control
Low Noise Constant Frequency Operation
Small Application Circuit
Regulated Output Current
Automatic Soft Start
No Inductors
16-Pin QFN44 Package
-40°C to +85°C Temperature Range
Applications
•
•
•
•
Color (RGB) Lighting
Programmable Current Source
White LED Backlighting
White LED Photo Flash for Digital Still Cameras
Typical Application
VIN
C1+
C1
1µF
VOUT
VBATTERY
CIN
1µF
EN/SET
COUT
1µF
C1C2+
AAT3134
EN/SET
C2
1µF
C2D1
D2
D3
D4
D5
D6
D4
D3
D2
D1
GND
D6
D5
Sub
Display
Main
Display
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
1
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
Pin Descriptions
Pin #
Symbol
1
2
3
4
5
6
7
8, 13
9
10
11
12
14
15
16
EP
D2
D5
D6
D3
D4
C1+
C1N/C
OUT
C2+
C2GND
IN
EN/SET
D1
Function
Current source output #2.
Current source output #5.
Current source output #6.
Current source output #3.
Current source output #4.
Flying capacitor 1 positive terminal. Connect a 1µF capacitor between C1+ and C1-.
Flying capacitor 1 negative terminal.
No connection.
Charge pump output. Requires 1µF capacitor connected between this pin and ground.
Flying capacitor 2 positive terminal. Connect a 1µF capacitor between C2+ and C2-.
Flying capacitor 2 negative terminal.
Ground.
Input power supply. Requires 1µF capacitor connected between this pin and ground.
Control pin.
Current source output #1.
Exposed paddle (bottom); connect to GND directly beneath package.
Pin Configuration
QFN44-16
(Top View)
13
15
14
EN/SET
16
1
12
GND
D5
2
11
C2-
D6
3
10
C2+
D3
4
9
OUT
8
7
6
5
N/C
C1-
C1+
D4
2
N/C
IN
D1
D2
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
Absolute Maximum Ratings1
Symbol
Description
VIN
VOUT
FB, VEN/SET
VEN/SET(MAX)
IOUT2
TJ
Input Voltage
Charge Pump Output
FB or EN/SET to GND Voltage
Maximum EN/SET to Input Voltage
Maximum DC Output Current
Operating Junction Temperature Range
Value
Units
-0.3 to 6.0
-0.3 to 6.0
-0.3 to 6.0
0.3
150
-40 to 150
V
V
V
V
mA
°C
Value
Units
Thermal Information3
Symbol
qJA
qJC
PD
Description
Thermal Resistance
Thermal Resistance
Maximum Power Dissipation
50
15
2
°C/W
W
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.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
3
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
Electrical Characteristics1
VIN = 3.5V, CIN = COUT = C1 = C2 = 1.0µF; TA = -40°C to +85°C. Unless otherwise noted, typical values are TA = 25°C.
Symbol
Description
Input Power Supply
VIN
Operation Range
ICC
Operating Current
ISHDN
Shutdown Current
IDX(MAX)
Maximum Output Current
Current Matching Between
I(D-Match)
Any Two Outputs
Charge Pump Section
TSS
Soft-Start Time
FCLK
Clock Frequency
Charge Pump Section Efficiency
hCP
EN/SET
VEN(L)
VEN(H)
TEN/SET LO
TEN/SET HI
TOFF
Input Current
Enable Threshold Low
Enable Threshold High
EN/SET Low Time
Minimum EN/SET High Time
EN/SET Off Timeout
EN/SET Input Leakage
Conditions
Min
Typ
2.7
3.0V ≤ VIN ≤ 5.5V, Active, No Load Current
EN/SET = 0
VIN = 3.6, Code = 32
VD1:D4 = 3.6, VIN = 3.5V
VD5:VD6 = 3.6, VIN = 3.5V
1.8
18
VIN = 3.5V, IOUT(TOTAL) = 120mA, Measured
from IN to OUT
20
0.5
0.5
Max
Units
5.5
3.5
1.0
22
V
mA
µA
mA
%
200
1000
µs
kHz
93
%
0.5
VEN/SET < 0.5
VEN/SET > 1.4
VEN/SET < 0.5
1.4
0.3
75
50
-1.0
500
1.0
V
V
µs
ns
µs
µA
1. The AAT3134 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls.
4
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
Typical Characteristics
Unless otherwise noted, VIN = 3.5V, CIN = COUT = C1 = C2 = 1µF, TA = 25°C.
IDIODE vs. Input Voltage
Efficiency vs. Input Voltage
(4x20mA)
(4x20mA)
90
95
85
90
VDIODE = 3.3V
80
85
VDIODE = 3.4V
75
80
IDIODE (mA)
Efficiency (%)
100
75
VDIODE = 3.5V
70
65
VDIODE = 3.6V
60
65
60
55
50
45
50
40
2.9
3.1
3.3
3.5
3.7
3.9
4.1 4.3
VDIODE = 3.4V VDIODE = 3.5V
VDIODE = 3.6V
70
55
2.7
VDIODE = 3.3V
4.5
4.7 4.9
5.1
2.7
2.9
3.1
3.3
3.5
Input Voltage (V)
Quiescent Current (mA)
3.9
4.1
4.3
4.5
4.7
4.9
5.1
Input Voltage (V)
Quiescent Current vs. Input Voltage
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
2.50
3.7
VIH and VIL vs. VIN
0.850
0.825
0.800
0.775
VIH
0.750
VDIODE = 3.3V
0.725
VDIODE = 3.4V
VIL
0.700
VDIODE = 3.5V
0.675
VDIODE = 3.6V
0.650
0.625
0.600
3.00
3.50
4.00
4.50
Input Voltage (V)
5.00
5.50
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
5
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
Typical Characteristics
Unless otherwise noted, VIN = 3.5V, CIN = COUT = C1 = C2 = 1µF, TA = 25°C.
Turn-On to Full-Scale Load Switch
Turn-On to Full-Scale Charge Pump
ENSET
(1V/div)
ENSET
(1V/div)
OUT
(2V/div)
OUT
(2V/div)
VDIODE
(1V/div)
VDIODE
(2V/div)
IIN
(200mA/div)
IIN
(100mA/div)
Time (50µs/div)
Time (50µs/div)
Charge Pump to Load Switch
Load Switch to Charge Pump
(80mA)
(80mA)
VIN
(10mV/div)
VIN
(20mV/div)
OUT
(2V/div)
OUT
(1V/div)
VDIODE
(2V/div)
VDIODE
(1V/div)
IIN
(100mA/div)
IIN
(200mV/div)
Time (50µs/div)
Time (50µs/div)
Turn-Off
80mA Load Characteristics
VIN
20mV/div
ENSET
(1V/div)
VDIODE
(2V/div)
IIN
(100mA/div)
VDIODE
Time (200µs/div)
6
OUT
Time (1µs/div)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
Functional Block Diagram
VIN
Soft-Start
Control
C1+
C11X/1.5X
Charge
Pump
1MHz
Oscillator
Voltage
Reference
C2+
C2OUT
D1
Current
Reference
Quad
Output
DAC
D2
D3
D4
32x16 bit
ROM
EN/SET
S2Cwire
Interface
Dual
Output
DAC
32x16 bit
ROM
D5
D6
GND
Functional Description
The AAT3134 is a dual mode load switch (1X) and high
efficiency (1.5X) fractional charge pump device intended
for white LED backlight applications. The fractional
charge pump consists of a low dropout linear voltage
regulator followed by a 1.5X charge pump with multiple
current source outputs. To maximize power conversion
efficiency, an internal feedback control sensing circuit
monitors the voltage required on the constant current
source outputs. This control circuit then sets the load
switch and charge pump functions based upon the input
voltage level versus the output voltage level needed.
This function significantly enhances overall device efficiency when the input voltage level is greater than the
voltage required at the constant current source outputs.
The 1X load switch/1.5X charge pump mode decision is
based on the voltage levels sensed on either the D1 or
D5 output, whichever is greater. Switchover between the
1.5X (charge pump) operating mode and the 1X (load
switch) mode occurs automatically (as a function of
input and output voltages) and does not require user
intervention to maintain maximum efficiency.
The AAT3134 requires only four external components:
two 1µF ceramic capacitors for the charge pump flying
capacitors (C1 and C2), one 1µF ceramic input capacitor
(CIN), and one 0.33µF to 1µF ceramic output capacitor
(COUT). The LDO/1.5X charge pump output is converted
into four (D1 to D4) constant current outputs to drive
four individual LEDs with a maximum current of 20mA
each and two (D5 and D6) constant current outputs with
a maximum current of 20mA. The current source output
magnitude is controlled by the EN/SET serial data interface. The interface records rising edges of the EN/SET
pin and decodes them into 32 addresses corresponding
to individual current level settings. The 32 addresses are
divided up such that outputs D1 to D4 can be controlled
independently of outputs D5 to D6. For Addresses 1 to
6, 7 to 12, 13 to 18, 19 to 24, and 25 to 30, outputs D1
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
7
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
Applications Information
to D4 start at 0mA and increase from 1mA to 20mA in
four steps. Outputs D5 and D6 remain constant over
these address ranges which provides orthogonal control
of the two channels. For Addresses 1 to 6, D5 and D6 are
set to 0mA, Addresses 7 to 12 are 1mA; Addresses 13 to
18 are 10mA; Addresses 19 to 24 are 12mA; and
Addresses 25 to 30 are 15mA. For maximum brightness
control, Addresses 31 and 32 set D5 and D6 to the
maximum 20mA level. For design flexibility, D1 to D4 are
set to 0mA at Address 31, and 20mA at Address 32. This
is summarized in Table 1 and Figure 1.
Constant Current Output Level Settings
The constant current source output amplitude for output
D1 to D4 and D5 to D6 are set via the serial interface
according to the scale described in Figure 1 and the previous section. Because the outputs D1 to D6 are true
independent constant current sources, the voltage
observed on any single given output will be determined
by the actual forward voltage (VF) for the LED being
driven.
The modulo 32 interface wraps back to State 1 after the
32nd clock. With each EN/SET pulse, the output current
changes to the next setting in the address decoding. To
change settings to the previous address decoding, 31
EN/SET clock pulses are required. The counter can be
clocked at speeds up to 1MHz, so that intermediate
states are not visible. The first rising edge of EN/SET
enables the IC and initially sets the output LED currents
to 0mA. Additional clocks are required to set the desired
current level. Once the final clock cycle is input for the
desired brightness level, the EN/SET pin is held high to
maintain the device output current at the programmed
level. The device is disabled 500µs after the EN/SET pin
transitions to a logic low state.
Since the output current of the AAT3134 is programmable through the S2Cwire serial interface, no PWM (pulse
width modulation) or additional control circuitry are
needed to control LED brightness. This feature greatly
reduces the burden on a microcontroller or system IC to
manage LED or display brightness, allowing the user to
“set it and forget it.” Furthermore, with its high-speed
serial interface (1MHz data rate), the output current of
the AAT3134 can be changed successively to brighten or
dim LEDs in smooth transitions (e.g., to fade out) or in
abrupt steps, giving the user complete programmability
and real-time control of LED brightness.
Output Current Level Settings
20
18
Current (mA)
16
14
12
10
8
6
4
2
0
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Address Code
Figure 1: Output Current Level Settings.
8
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
clocked at speeds up to 1MHz, so that intermediate
states are not visible. The first rising edge of EN/SET
enables the IC and initially sets the output LED current
to 0. Once the final clock cycle is input for the desired
brightness level, the EN/SET pin is held high to maintain
the device output current at the programmed level. The
device is disabled 500µs after the EN/SET pin transitions
to a logic low state. The EN/SET timing is designed to
accommodate a wide range of data rates. After the first
rising edge of EN/SET, the charge pump is enabled and
reaches full capacity after the soft-start time (TSS).
During the soft-start time, multiple clock pulses may be
entered on the EN/SET pin to set the final output current
level with a single burst of clocks. Alternatively, the EN/
SET clock pulses may be entered one at a time to gradually increase the LED brightness over any desired time
period. A constant current is sourced as long as EN/SET
remains in a logic high state. The current source outputs
are switched off after EN/SET has remained in a low
state for at least the TOFF timeout period.
Current Level Settings (mA)
Address
D1 to D4
D5 to D6
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
0
1
10
12
15
20
0
1
10
12
15
20
0
1
10
12
15
20
0
1
10
12
15
20
0
0
0
0
0
0
0
1
1
1
1
1
1
10
10
10
10
10
10
12
12
12
12
12
12
15
26
1
15
27
28
29
30
31
32
10
12
15
20
0
20
15
15
15
15
20
20
LED Selection
The AAT3134 is specifically intended for driving white
LEDs. However, the device design will allow the AAT3134
to drive most types of LEDs with forward voltage specifications ranging from 2.0V to 4.3V. LED applications
may include main and sub-LCD display backlighting,
camera photo-flash applications, color (RGB) LEDs,
infrared (IR) diodes for remotes, and other loads benefiting from a controlled output current generated from a
varying input voltage. Since the D1 to D6 output current
sources are matched with negligible voltage dependence, the LED brightness will be matched regardless of
the specific LED forward voltage (VF) levels.
Table 1: Constant Current Source Output
Programming Levels.
EN/SET Serial Interface
The current source output magnitude is controlled by the
EN/SET serial interface. The interface records rising
edges of the EN/SET pin and decodes them into 32 individual current level settings, as summarized in Table 1.
The modulo 32 interface wraps back to State 1 after the
32nd clock, so that the previous state is achieved by
clocking the EN/SET pin 31 times. The counter can be
In some instances (e.g., in high luminous output applications such as photo flash), it may be necessary to
drive high-VF type LEDs. The low dropout current sources in the AAT3134 make it capable of driving LEDs with
forward voltages as high as 4.3V at full current from an
input supply as low as 3.0V. Outputs can be paralleled to
drive high-current LEDs without complication.
EN/SET Timing Diagram
tHI
tOFF
tLO
EN/SET
Code
OFF
1
2
3
OFF
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
9
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
Device Switching Noise Performance
Load Switch Mode Efficiency
The AAT3134 operates at a fixed frequency of approximately 1MHz to control noise and limit harmonics that
can interfere with the RF operation of cellular telephone
handsets or other communication devices. Back-injected
noise appearing on the input pin of the charge pump is
20mV peak-to-peak, typically ten times less than inductor-based DC/DC boost converter white LED backlight
solutions. The AAT3134 soft-start feature prevents noise
transient effects associated with inrush currents during
start-up of the charge pump circuit.
The AAT3134 load switch mode is operational at all times
and functions alone to enhance device power conversion
efficiency when the condition exists where VIN is greater
than voltage across the load connected to the constant
current source outputs. When in load switch mode, the
voltage conversion efficiency is defined as output power
divided by input power:
Power Efficiency and Device Evaluation
The expression to define the ideal efficiency (h) can be
rewritten as:
The charge pump efficiency discussion in the following
sections only accounts for efficiency of the charge pump
section itself. Due to the unique circuit architecture and
design of the AAT3134, it is very difficult to measure
efficiency in terms of a percent value comparing input
power over output power.
Since the AAT3134 outputs are pure constant current
sources and typically drive individual loads, it is difficult
to measure the output voltage for a given output (D1 to
D6) to derive an overall output power measurement. For
any given application, white LED forward voltage levels
can differ, yet the output drive current will be maintained
as a constant.
This makes quantifying output power a difficult task
when taken in the context of comparing to other white
LED driver circuit topologies. A better way to quantify
total device efficiency is to observe the total input power
to the device for a given LED current drive level. The
best white LED driver for a given application should be
based on trade-offs of size, external components count,
reliability, operating range, and total energy usage...not
just % efficiency.
The AAT3134 efficiency may be quantified under very
specific conditions and is dependent upon the input voltage versus the output voltage seen across the loads
applied to outputs D1 through D6 for a given constant
current setting. Depending upon VIN being greater than
the specific voltage seen across the load on D1 (or D6),
the device will operate in load switch mode. If VIN is less
than the voltage required on the constant current source,
the device will operate in 1.5X charge pump mode. Each
of these two modes will yield different efficiency values.
One should refer to the following two sections for explanations for each operational mode.
10
η=
η=
POUT
PIN
POUT VOUT ∙ IOUT VOUT
=
=
PIN
VIN ∙ IOUT
VIN
-or-
η(%) = 100
 VOUT 
 VIN 
Charge Pump Section Efficiency
The AAT3134 contains a fractional charge pump which
will boost the input supply voltage when VIN is less than
the voltage required on the constant current source outputs. The efficiency (h) can be simply defined as a linear
voltage regulator with an effective output voltage that is
equal to one and one half times the input voltage.
Efficiency (h) for an ideal 1.5X charge pump can typically be expressed as the output power divided by the
input power:
η=
POUT
PIN
In addition, with an ideal 1.5X charge pump, the output
current may be expressed as 2/3 of the input current.
The expression to define the ideal efficiency (h) can be
rewritten as:
η=
POUT
VOUT ∙ IOUT
V
=
= OUT
PIN
VIN ∙ 1.5IOUT 1.5VIN
-or-
η(%) = 100
 VOUT 
 1.5VIN
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
For a charge pump with an output of 5V and a nominal
input of 3.5V, the theoretical efficiency is 95%. Due to
internal switching losses and IC quiescent current consumption, the actual efficiency can be measured at
93%. These figures are in close agreement for output
load conditions from 1mA to 100mA. Efficiency will
decrease as load current drops below 0.05mA or when
the level of VIN approaches VOUT. Refer to the Typical
Characteristics section of this document for measured
plots of efficiency versus input voltage and output load
current for the given charge pump output voltage
options.
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 100mW. A
value of 1µF for all four capacitors is a good starting
point when choosing capacitors. If the LED current
sources are only programmed for light current levels,
then the capacitor size may be decreased.
Capacitor Characteristics
Ceramic composition capacitors are highly recommended over all other types of capacitors for use with the
AAT3134. Ceramic capacitors offer many advantages
over their tantalum and aluminum electrolytic counterparts. A ceramic capacitor has very low ESR, is lowest
cost, has a smaller PCB footprint, and is non-polarized.
Low ESR ceramic capacitors help to 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
have tight tolerance and are stable over temperature.
Large capacitor values are typically composed of X7R,
X5R, Z5U, or Y5V dielectric materials. Large ceramic
capacitors, greater than 2.2µF, are often available in
low-cost Y5V and Z5U dielectrics, but capacitors greater
than 1µF are usually not required for AAT3134 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 AAT3134 has a thermal protection circuit that will
shut down the internal LDO and charge pump if the die
temperature rises above the thermal limit, as is the case
during a short-circuit of the OUT pin.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
11
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
VIN
C1+
C1
1µF
C1C2+
VOUT
VBATTERY
CIN
1µF
C OUT
1µF
AAT3134
C2
1µF
D1
D2
D3
D4
RB*
RB*
RB*
RB*
C2-
EN/SET
EN/SET
GND
Resistor R is optional
D1
D2
D3
D4
D5
D6
D5
R
D6
R
Resistor R is optional
*In some applications, white LED forward voltages (VF) can vary significantly. Ballast resistors between the LED cathodes and ground are recommended
for balancing the forward voltage differences. The ballast resistor value may be approximated by the following equation:
RB =
VSOURCE - VF
IF
Figure 2: AAT3134 Driving Two Groups of Paralleled White LEDs
(e.g., main and sub-LCD backlights).
12
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
DATA SHEET
AAT3134
High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
QFN44-16
JBXYY
AAT3134ISN-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
QFN44-163
Pin 1 Dot By Marking
0.230 ± 0.050
Pin 1 Identification
0.500 ± 0.050
Top View
1.250 ± 0.050
5
C0.3
13
9
1.250 ± 0.050
0.025 ± 0.025
Bottom View
0.214 ± 0.036
0.900 ± 0.100
3.000 ± 0.050
0.400 ± 0.100
3.000 ± 0.050
1
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.
Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved.
Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. These materials, including the information contained herein, are provided by Skyworks as a
service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Skyworks may change its documentation, products, services, specifications or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no
responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from any future changes.
No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided hereunder, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale.
THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR
PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES
NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES, INCLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM
THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the Skyworks products could lead to personal injury, death, physical or environmental damage. Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper
use or sale.
Customers are responsible for their products and applications using Skyworks products, which may deviate from published specifications as a result of design defects, errors, or operation of products outside of published parameters or design specifications. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product
design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters.
Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for
identification purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202138A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 5, 2012
13