DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
General Description
Features
The AAT3104 is a charge-pump based, current-source
white LED driver capable of driving one to four LEDs up
to 30mA, each. It automatically switches between 1x
mode and 2x mode to maintain the highest efficiency
and optimal LED current accuracy and matching.
• Drives up to 4 LEDs at up to 31mA each
• Automatic Switching Between 1x and 2x Modes
• 1MHz Switching Frequency
• Linear LED Output Current Control
• Single-wire, S2Cwire Interface
AAT3104-1: 16-step
AAT3104-2: 32-step
• ±10% LED Output Current Accuracy
• ±3% LED Output Current Matching
• Low-current Shutdown Mode
• Built-in Thermal Protection
• Automatic Soft-start
• Available in 2x2mm SC70JW-10 Package
The AAT3104 charge pump’s 1x mode (bypass mode)
has very low resistance allowing LED current regulation
to be maintained with input supply voltage approaching
the LED forward voltage.
LED brightness is controlled using Skyworks' patented
S2Cwire™ single wire interface. The AAT3104 is available
in a 2x2mm 10-lead SC70JW-10 package.
Applications
• Cordless Phone Handsets
• Digital Cameras
• Mobile Phone Handsets
• MP3 and PMP Players
Typical Application
Input Voltage
2.7V to 5.5V
IN
C+
C IN
1µF
CP
1µF
OUT
AAT3104
D1
D2
CEN/SET
S2Cwire
Interface
C OUT
1µF
D3
EN/SET
D4
GND
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Pin Descriptions
Pin#
Name
1
D2
2
D1
3
OUT
4
5
6
CC+
GND
7
EN/SET
8
IN
9
D4
10
D3
Description
LED2 Current Source Output. D2 is the output of LED2 current source. Connect LED2’s anode to D2
and its cathode to GND.
LED1 Current Source Output. D1 is the output of LED1 current source. Connect LED1’s anode to D1
and its cathode to GND.
Charge Pump Output. OUT is the output of the charge pump. Bypass OUT to GND with a 1μF or
larger ceramic capacitor.
Charge Pump Capacitor Negative Node.
Charge Pump Capacitor Positive Node. Connect a 1μF ceramic capacitor between C+ and C-.
Analog Ground. Connect this pin to the system’s analog ground plane.
LED Enable and serial control input. EN/SET is the ON/OFF control for the LED and the S2Cwire digital
input for the AAT3104-1/-2 to control serially the LED brightness according to the maximum current.
Power source input. Connect IN to the power source, typically the battery. Bypass IN to GND with a
1μF or larger ceramic capacitor.
LED4 Current Source Output. D4 is the output of LED4 current source. Connect LED4’s anode to D4
and its cathode to GND.
LED3 Current Source Output. D3 is the output of LED3 current source. Connect LED3’s anode to D3
and its cathode to GND.
Pin Configuration
SC70JW-10
(Top View)
D2
D1
OUT
CC+
2
1
10
2
9
3
8
4
7
5
6
D3
D4
IN
EN/SET
GND
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Absolute Maximum Ratings1
Symbol
VIN, VOUT, VC+,
VC-, VD1...4
VEN/SET
TS
TJ
TLEAD
Description
IN, C+, C-, OUT, D1, D2, D3, and D4 Pin Voltages to GND
EN/SET Pin Voltage to GND
Storage Temperature Range
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Value
Units
-0.3 to 6.0
V
-0.3 to VIN + 0.3
-65 to 150
-40 to 150
300
V
°C
°C
°C
Value
Units
625
160
mW
°C/W
Thermal Information
Symbol
PD
θJA
Description
Maximum Power Dissipation2, 3
Maximum Thermal Resistance3
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 circuit board.
3. Derate 6.25mW/°C above 40°C ambient temperature.
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Electrical Characteristics1
IN = EN = 3.6V, CIN = 1µF, COUT = 1µF, C1 = 1µF, TA = -40°C to 85°C unless otherwise noted. Typical values are at TA
= 25°C.
Symbol
Description
Conditions
Input Power Supply
VIN
Input Voltage Range
Iq
Quiescent Current
IIN
Typ
Max
Units
5.5
6
V
mA
3.5
mA
6
mA
2.7
No Load Operating Current
IIN(SHDN)
Input Shutdown Current
Charge Pump Section
IOUT
OUT Maximum Output Current
VOUT
Charge Pump Output Voltage
fOSC
Charge Pump Oscillator Frequency
VIN_(TH)
Charge Pump Mode Hysteresis
tOUT
LED Output Current Start-up Time
AAT3104-1/-2: LED Current Source Outputs
D1 – D4 Current Accuracy
ID_(MAX)
(AAT3104-1 only)
D1 – D4 Current Accuracy
ID_(MAX)
(AAT3104-2 only)
ΔID_(MAX)
D1 – D4 Current Matching
D1 – D4 Current Accuracy
ID_(DATA15)
(AAT3104-1 only)
D1 – D4 Current Accuracy
ID_(DATA29)
(AAT3104-2 only)
VD_(TH)
Min
D1- D4 Charge Pump Mode Transition
Threshold
AAT3104-1/-2: EN/SET and S Cwire Control
VENH
EN/SET Input High Threshold Voltage
VENL
EN/SET Input Low Threshold Voltage
IEN(LKG)
EN/SET Input Leakage Current
tEN/SET(OFF) EN/SET Input OFF Timeout
tEN/SET(LAT) EN/SET Input Latch Timeout
tEN/SET(LOW) EN/SET Input Low Time
tENSET(H-MIN) EN/SET Minimum High Time
tENSET(H-MAX) EN/SET Maximum High Time
IN = 5.5V, EN = IN, VD1 = VD2 = VD3 = 0V
IN = 5.5V, EN = IN, ID1 = ID2 = ID3 = ID4
= FS, VD1 = VD2 = VD3 = VD4 = IN – 1.5V,
Exclude IDN current, 1x mode
Operating, ID1 = ID2 = ID3 = ID4 = OPEN,
2x mode
EN/SET = GND
1
μA
0.6
150
5
0.8
150
190
DATA = 1, VIN – VF = 1.5V
27
30
33
mA
DATA = 1, VIN – VF = 1.5V
28
31
34
mA
When charge pump is on
ID1 = ID2 = ID3 = ID4 =30mA
EN/SET =IN
DATA = 1, VIN – VF = 1.5V
1.05
250
±3
mA
V
MHz
mV
μs
%
DATA = 15, VIN – VF = 1.5V
1.6
2.0
2.4
mA
DATA = 29, VIN – VF = 1.5V
1.6
2.0
2.4
mA
ID1 = ID2 = ID3 = ID4 = 30mA, VIN – VD1 is
measured
ID1 = ID2 = ID3 = ID4 = 20mA, VIN – VD1 is
measured
380
mV
350
mV
2
1.4
EN/SET = IN = 5V
0.4
1
500
500
75
-1
0.3
50
75
V
V
μA
µs
µs
µs
ns
µs
1. The AAT3104 is guaranteed to meet performance specification over the -40°C to 85°C operating temperature range and are assured by design, characterization and correlation
with statistical process controls.
4
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Typical Characteristics
VIN = 3.6V, CIN = COUT = C1 = 1μF; TA = 25°C, unless otherwise noted.
1X Mode Turn-On Waveform
2X Mode Turn-On Waveform
(VIN = 4.2V; Load = 120mA)
VLED
(2V/div)
(VIN = 3.6V; Load = 120mA)
VLED
(2V/div)
0
0
IIN
(200mA/div)
0
IIN
(250mA/div)
0
VOUT
(2V/div)
0
VOUT
(2V/div)
0
EN
(1V/div)
0
EN
(1V/div)
0
Time (200µs/div)
Time (200µs/div)
2X Mode Turn-Off Waveform
2X Mode Output Ripple
(VIN = 3.6V; Load = 120mA)
IIN
(250mA/div)
(VIN = 3.6V; Load = 120mA)
VOUT
(AC Coupled)
(20mV/div)
0
VLED
(2V/div)
0
EN
(1V/div)
0
VIN
(AC Coupled)
(5mV/div)
0
Time (200µs/div)
0
Time (0.4µs/div)
1mA to 30mA LED Current Step
30mA to 1mA LED Current Step
(VIN = 4.2V)
(VIN = 4.2V)
VLED
2V/div
IIN
200mA/div
VOUT
2V/div
EN
1V/div
VLED
(2V/div)
0
IIN
(200mA/div)
VOUT
(2V/div)
0
0
EN
(1V/div)
0
Time (80µs/div)
0
0
0
0
Time (80µs/div)
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Typical Characteristics
VIN = 3.6V, CIN = COUT = C1 = 1μF; TA = 25°C, unless otherwise noted.
Current Matching vs. Temperature
Efficiency vs. Input Voltage
(AAT3104-2; Code = 1)
33.0
90
D1
D2
D3
D4
32.0
31.5
VF = 2.7V
VF = 3.0V
VF = 3.3V
VF = 3.6V
80
Efficiency (%)
32.5
Current (mA)
(ILED = 31mAx4; Voltage Sweep Upwards)
31.0
30.5
30.0
70
60
50
40
29.5
29.0
-40
-15
10
35
60
30
85
Temperature (°C)
2.7
4.3
4.7
5.1
5.5
Quiescent Current vs. Input Voltage
6.5
Quiescent Current (mA)
90
80
Efficiency (%)
3.9
Input Voltage (V)
Efficiency vs. Input Voltage
70
60
50
VF = 2.7V
VF = 3.0V
VF = 3.3V
VF = 3.6V
40
30
2.7
3.1
3.5
3.9
4.3
4.7
5.1
6.0
5.5
5.0
4.5
4.0
3.5
85°C
25°C
-40°C
3.0
2.5
2.0
2.7
5.5
Input Voltage (V)
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
Shutdown Current vs. Temperature
Frequency vs. Temperature
25
850
VIN = 5.5V
VIN = 2.7V
20
840
Frequency (KHz)
ShutdownnCurrent (nA)
3.5
(ILED = 31mAx4; Voltage Sweep Downwards)
15
10
5
830
820
810
800
790
780
770
760
0
-40
-15
10
35
Temperature (°C)
6
3.1
60
750
-40
85
-15
10
35
60
Temperature (°C)
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Typical Characteristics
VIN = 3.6V, CIN = COUT = C1 = 1μF; TA = 25°C, unless otherwise noted.
No Load Operating Current vs. Input Voltage
(2x Mode)
1.2
85°C
25°C
-40°C
6.2
6.0
1.0
VEN(H) (V)
Operating Current (mA)
6.4
EN Input High Threshold Voltage
vs. Input Voltage
5.8
5.6
0.8
0.6
5.4
5.0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
0.2
2.7
5.5
Input Voltage (V)
300
TEN/SET(LAT) (µs)
VEN(L) (V)
1.0
0.8
0.6
85°C
25°C
-40°C
0.4
3.9
4.3
4.7
3.9
4.3
4.7
5.1
5.5
EN/SET Input Latch Timeout
vs. Input Voltage
330
3.5
3.5
Input Voltage (V)
1.2
3.1
3.1
EN Input Low Threshold Voltage
vs. Input Voltage
0.2
2.7
85°C
25°C
-40°C
0.4
5.2
5.1
270
240
210
85°C
25°C
-40°C
180
150
2.7
5.5
Input Voltage (V)
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
EN/SET Input OFF Timeout
vs. Input Voltage
400
TEN/SET(OFF) (µs)
350
300
250
85°C
25°C
-40°C
200
150
2.7
3.1
3.5
3.9
4.3
Input Voltage (V)
4.7
5.1
5.5
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Functional Block Diagram
C+
C–
OUT
D1
IN
Two-Mode
CP Control
VF Monitoring
D2
4
D3
2x
D4
1x
5
EN/SET
S2Cwire Control
Functional Description
The AAT3104 is a low-cost charge-pump solution
designed to drive up to four white LEDs. The charge
pump operates from a 2.7V to 5.5V power source and
converts it to voltage levels necessary to drive the LEDs.
LED current is individually controlled through integrated
current sources powered from the output of the charge
pump. Low 1x charge-pump output resistance and lowdrop voltage current sources allow the charge pump to
remain in 1x mode with an input voltage as low as 3.8V
and LED forward voltages of 3.5V. Once in 2x mode, the
charge pump monitors the input supply voltage and
automatically switches back to 1x mode when there is
sufficient input voltage.
The AAT3104 requires only three external components:
one 1μF ceramic capacitor for the charge pump flying
capacitor (CP), one 1μF ceramic input capacitor (CIN), one
8
IREF
GND
5 Bits DAC
1μF ceramic output capacitor (COUT). The four constant
current outputs of the AAT3104 (D1 to D4) can drive four
individual LEDs with a maximum current of 30mA each.
Skyworks' S2Cwire serial interface enables the AAT31041/-2 and changes the current source magnitudes through
the EN/SET pin.
S2Cwire Serial Interface
The LED output current of the AAT3104 is controlled by
Skyworks' S2Cwire serial interface. Since the LED current
is programmable, no PWM or additional control circuitry
is 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.” With its high-speed serial interface
(1MHz data rate), the LED current can be changed quickly and easily. Also, the non-pulsating LED current reduc-
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
es system noise and improves LED reliability. The S2Cwire
interface relies on the number of rising edges to the EN/
SET pin to set the register. A typical write protocol is a
burst of EN/SET rising edges, followed by a pause with
EN/SET held high for at least tLAT (500μs). The programmed current is then seen at the current source outputs. When EN/SET is held low for an amount of time
longer than tOFF (500μs), the AAT3104 enters into shutdown mode and draws less than 1μA from the input and
the internal data register is reset to zero.
The AAT3104-1/2’s serial interface reduces the LED current on each rising pulse of the enable input. If the
AAT3104 is in shutdown, the first rising edge of the EN/
SET input turns on the LED driver to the maximum current. Successive rising edges decrease the LED current
as shown in Table 1 and Figure 2 for the AAT3104-1. For
the AAT3104-2, Table 2 and Figure 3 illustrate a 32-step
LED current control profile.
Data
EN Rising
Edges
D1-D4
Current (mA)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0.5
Data
EN Rising Edges
D1-D4 Current (mA)
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
26
27
28
29
30
31
32
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
26
27
28
29
30
31
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
0.5
Table 2: AAT3104-2 LED Current Settings.
Table 1: AAT3104-1 LED Current Settings.
tLO
t HI
OFF
1
tOFF
2
3
OFF
Figure 1: EN/SET Timing Diagram.
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
22.5
15.0
7.5
0
Dx Output Current (mA)
Dx Output Current (mA)
30.0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
S C Wire Interface Data Code
2
25
20
15
10
5
0
1
Figure 2: AAT3104-1 Current Control Profile.
Applications Information
LED Selection
The AAT3104 is specifically designed for driving white
LEDs. However, the device design will allow the AAT3104
to drive most types of LEDs with forward voltage specifications ranging from 2.2V to 4.7V. LED applications
may include mixed arrangements for display backlighting, keypad display, and any other application needing a
constant current source generated from a varying input
voltage. Since the D1 to D4 constant current sources are
matched with negligible supply voltage dependence, the
constant current channels will be matched regardless of
the specific LED forward voltage (VF) levels.
The low dropout current sources in the AAT3104 maximize performance and make it capable of driving LEDs
with high forward voltages. Multiple channels can be
combined to obtain a higher LED drive current without
complication.
All unused LED source pins should be connected to GND
or left floating. Do not connect to the OUT pin.
Device Switching Noise Performance
The AAT3104 operates at a fixed frequency of approximately 1MHz to control noise and limit harmonics that
can interfere with the RF operation of mobile 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 AAT3104
soft-start feature prevents noise transient effects associated with inrush currents during start-up of the charge
pump circuit.
10
30
3
5
7
9
11 13 15 17 19 21 23 25 27 29 31
S2C Wire Interface Data Code
Figure 3: AAT3104-2 Current Control Profile.
Shutdown
Since the current switches are the only power returns for
all loads, there is no leakage current when all source
switches are disabled. To enter shutdown operation, the
EN/SET input for the AAT3104-1/2 should be strobed
low. After tOFF (500μs), AAT3104 will be shut down and
typically draws less than 1μA from the input. Registers
are reset to 0 in shutdown.
Power Efficiency and Device Evaluation
The charge pump efficiency discussion in the following
sections accounts only for efficiency of the charge pump
section itself. Due to the unique circuit architecture and
design of the AAT3104, it is very difficult to measure
efficiency in terms of a percent value comparing input
power over output power.
Since the AAT3104 outputs are pure constant current
sources and typically drive individual loads, it is difficult
to measure the output voltage for a given output 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 component count,
reliability, operating range, and total energy usage, not
just output power over input power efficiency.
The AAT3104 efficiency may be quantified under very
specific conditions and is dependent upon the input voltage versus the output voltage across the loads applied
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DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
to outputs D1 through for a given constant current setting. Depending on the combination of VIN and voltages
sensed at the current sources, the device will operate in
load switch mode. When any one of the voltages sensed
at the current sources nears dropout, the device will
operate in 2X charge pump mode.
Each of these modes will yield different efficiency values.
Refer to the following two sections for explanations for
each operational mode.
1X Mode Efficiency
The AAT3104 1X mode is operational at all times and
functions alone to enhance device power conversion efficiency when VIN is higher than the voltage across the
load. When in 1X mode, voltage conversion efficiency is
defined as output power divided by input power.
An expression for the ideal efficiency (η) in 1X chargepump mode can be expressed as:
POUT VF · ILED VF · ILED VF
≈
η= P = V ·I =V ·I
VIN
IN
IN
IN
IN
OUT
-or
VF
η (%) = V · 100
IN
For a charge pump led driver with VF of 3.2V and 4.2V
input voltage, the theoretical efficiency is 76%. Due to
internal switching losses and IC quiescent current consumption, the actual efficiency can be measured at 73%.
2X Charge Pump Mode Efficiency
The AAT3104 contains a charge pump which will boost
the input supply voltage in the event where VIN is less
than the voltage required to supply the output. The efficiency (η) can be simply defined as a linear voltage
regulator with an effective output voltage that is equal to
one and two times the input voltage. Efficiency (η) for an
ideal 2X charge pump can typically be expressed as the
output power divided by the input power.
η=
PF
PIN
In addition, with an ideal 2X charge pump, the output
current may be expressed as 1/3 of the input current.
The expression to define the ideal efficiency (η) can be
rewritten as
POUT VF · ILED
VF · ILED
VF
η= P = V ·I =V ·2·I
≈ 2·V
IN
IN
IN
IN
OUT
IN
or
VF
η (%) = 2 · V · 100
IN
For a charge pump current source driver with VF of 3.2V
and 2.7V input voltage, the theoretical efficiency is 59%.
Due to internal switching losses and IC quiescent current
consumption, the actual efficiency can be measured at
57%. Efficiency will decrease substantially as load current drops below 1mA or when the voltage level at VIN
approaches the voltage level at VOUT.
Additional Applications
The current sources of the AAT3104 can be combined
freely to drive higher current levels through one LED. As
an example, a single LED can be driven at 120mA by
combining together D1 through D4 outputs.
For lower-cost applications, the flying capacitor can be
removed; C+ and C- should be floating. This will force
AAT3104 to operate in 1X mode. To maintain regulated
LED current, the input supply voltage has to be higher
than the charge-pump's dropout voltage in 1X mode plus
the forward voltage of the LED at the preset LED
current.
Capacitor Selection
Careful selection of the three external capacitors CIN, CP,
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 100mΩ. A value of
1μF for all four capacitors is a good starting point when
choosing capacitors. If the constant 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
AAT3104. 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 maximizing
charge pump transient response. Since ceramic capacitors are non-polarized, they are not prone to incorrect
connection damage.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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11
DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Input Voltage
2.7V to 5.5V
IN
C+
C IN
1µF
CP
1µF
OUT
C OUT
1µF
AAT3104
D1
D2
C-
D3
EN/SET
S2Cwire
Interface
D4
EN/SET
GND
Figure 4: Higher Current, Single LED Application.
Input Voltage
> VF + VDROP
IN
C+
C IN
1µF
OUT
AAT3104
D1
D2
CEN/SET
S2Cwire
Interface
C OUT
1µF
D3
EN/SET
D4
GND
Figure 5: Lower Cost 1X Mode Application.
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. Large
ceramic capacitors (i.e., larger than 2.2μF) are often
available in low cost Y5V and Z5U dielectrics, but capac-
12
itors larger than 1μF are not typically required for
AAT3104 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.
Evaluation Board Layout
When designing a PCB for the AAT3104, the key requirements are:
1. Place two flying capacitors C1 and C2 as close to the
chip as possible; otherwise 2x mode performance
will be compromised.
2. Place input and output decoupling capacitors as
close to the chip as possible to reduce switching
noise and output ripple.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202124A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 2, 2012
DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Evaluation Board Schematic
DC+
DC-
J1
DC+
C
10uF
1
2
VIN
3
C2
1µF
OUT
JP1
D4 D3 D2 D1
JP2
JP5
C1
1µF
1
2
CC+
IN
3
4
5
U1
D2
D3
D1
D4
OUT
VIN
CEN/SET
C+
GND
JP3
JP4
10
9
8
7
6
EN
AAT3104
C3
1µF
EN
S2C
R2
20K
C6
4.7µF
R5 R4 R3
1K 1K 1K
S1
S1
UP
1
2
3
4
U2
PIC12F675
VDD
GP5
GP4
GP3
VSS
GP0
GP1
GP2
VR1
POT10K
8
7
6
5
C4
0.1µF
R7
330
LED2
Red
MCU Power
R6
330
S2
S2
DOWN
LED1
Green
S2C
S3
S3
CYCLE
Figure 6: AAT3104 Evaluation Board Schematic.
Figure 7: AAT3104 Evaluation Board
Top Layer.
Figure 8: AAT3104 Evaluation Board
Bottom Layer.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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13
DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Ordering Information
Package
Interface
Current Control, Inverting
Marking1
Part Number (Tape and Reel)2
SC70JW-10
SC70JW-10
S2Cwire
S2Cwire
16-step
32-step
4DXYY
AAT3104IJQ-1-T1
AAT3104IJQ-2-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
SC70JW-10
2.20 ± 0.20
1.75 ± 0.10
0.40 BSC
0.225 ± 0.075
Top View
0.100
7° ± 3°
0.45 ± 0.10
4° ± 4°
0.05 ± 0.05
0.15 ± 0.05
1.10 MAX
0.85 ± 0.15
2.00 ± 0.20
2.10 ± 0.30
Side View
End View
All dimensions in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
14
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202124A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 2, 2012
DATA SHEET
AAT3104
Low Cost 1x/2x Four-Channel Charge Pump WLED Driver
Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved.
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