AAT3192 - Skyworks Solutions, Inc.

DATA SHEET
AAT3192: Two-Channel Charge Pump LED Driver
Applications
Description
• Entry level cordless phone handsets
The AAT3192 is a charge-pump based, current-sink white LED
driver capable of driving one or two LEDs up to 30 mA each. It
automatically switches between 1X mode and 2X mode to
maintain the highest efficiency and optimal LED current accuracy
and matching.
• Entry level digital cameras
• Entry level mobile phone handsets
• Entry level MP3 and PMP players
The AAT3192 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.
Features
• Drives up to two LEDs at up to 30 mA each
• Automatic switching between 1X and 2X modes
• 0.9 MHz switching frequency
The AAT3192 is available in a 2.0 × 2.2 mm, 10-lead SC70JW-10
package.
A typical application circuit is shown in Figure 1. The pin
configuration is shown in Figure 2. Signal pin assignments and
functional pin descriptions are provided in Table 1. Part number
descriptions are given in Table 2.
• Linear LED output current control:
− Single-wire, S2Cwire interface
 AAT3192-1: 16-step
 AAT3192-2: 8-step
 AAT3192-3: 4-step
− ON/OFF or PWM interface
 AAT3192-4
• ±10% LED output current accuracy
• ±3% LED output current matching
• Low-current shutdown mode
• Built-in thermal protection
• Automatic soft start
• SC70JW-10 (10-lead, 2.0 × 2.2 mm) package (MSL1, 260 °C
per JEDEC-J-STD-020)
Figure 1. AAT3192-1 Typical Application Circuit
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Figure 2. AAT3192 SC70JW-10
(Top View)
Table 1. AAT3192 Signal Descriptions
Pin #
Name
1
N/C
No connection.
2
OUT
Charge pump output. OUT is the output of the charge pump. Bypass OUT to GND with a 1 µF or larger ceramic
capacitor.
3
C−
Charge pump capacitor negative node.
4
C+
Charge pump capacitor positive node. Connect a 1 µF ceramic capacitor between C+ and C−.
5
IN
Power source input. Connect IN to the power source, typically the battery. Bypass IN to GND with a 1 µF or larger
ceramic capacitor.
EN/SET
(AAT3192-1/-2/-3)
LED enable and serial control input. EN/SET is the ON/OFF control for the LED and the S2Cwire digital input for the
AAT3192-1/-2/-3 to control serially the LED brightness according to the maximum current set by RSET.
6
EN/PWM
(AAT3192-4)
7
Description
LED ON/OFF and Pulse Width Modulation (PWM) control input. This logic input controls the LED outputs for the
AAT3192-4. Alternatively, a PWM signal from a GPIO or an equivalent signal from a separate controller can be used to
control LED output current linearly. A PWM signal, ranging from 10% to 100% duty cycle, controls the LED current
linearly between Zero Scale (ZS) and Full Scale (FS).
RSET
A 1% tolerance resistor from this pin to GND sets the maximum LED current level. For optimal LED output current
accuracy and matching in the AAT3192-1/-2/-4, a 14.3 kΩ resistor sets each full-scale output current to 20 mA,
maximum. For the AAT3192-3, an 11.5 kΩ resistor is recommended.
8
GND
Ground. Connect this pin to the system’s ground plane.
9
D2
LED2 current sink input. D2 is the input of LED2 current sink. Connect LED2’s anode to OUT and its cathode to D2.
10
D1
LED1 current sink input. D1 is the input of LED1 current sink. Connect LED1’s anode to OUT and its cathode to D1.
Table 2. Part Number Descriptions
Part Number
Interface
Current Control, Inverting
AAT3192IJQ-1
S2Cwire
16-step
2
8-step
AAT3192IJQ-3
2
S Cwire
4-step
AAT3192IJQ-4
PWM
Linear
AAT3192IJQ-2
S Cwire
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Electrical and Mechanical Specifications
Typical performance characteristics of the AAT3192 are illustrated
in Figures 3 through 18.
The absolute maximum ratings of the AAT3192 are provided in
Table 3, and electrical specifications are provided in Table 4.
Table 3. AAT3192 Absolute Maximum Ratings (Note 1)
Parameter
Symbol
Minimum
IN, C+, C−, OUT, D1, D2, and RSET pin voltages to GND
VIN, VC+, VC−, VOUT, VD1, VD2, VREST
EN/SET or EN/PWM pin voltage to GND
Operating junction temperature range
Maximum soldering temperature (at leads, 10 seconds)
Typical
Maximum
Units
−0.3
+6.0
V
VEN
−0.3
VIN + 0.3
V
TJ
−40
+150
°C
TLEAD
300
°C
Maximum thermal resistance (Note 2)
θJA
625
ºC/W
Maximum power dissipation (Note 2, 3)
PD
160
mW
Note 1: Exposure to maximum rating conditions for extended periods may reduce device reliability. There is no damage to device with only one parameter set at the limit and all other
parameters set at or below their nominal value. Exceeding any of the limits listed may result in permanent damage to the device.
Note 2: Mounted on an FR4 circuit board.
Note 3: Derate 6.25 mW/°C above 40 °C ambient temperature.
CAUTION: Although this device is designed to be as robust as possible, Electrostatic Discharge (ESD) can damage this device. This device
must be protected at all times from ESD. Static charges may easily produce potentials of several kilovolts on the human body
or equipment, which can discharge without detection. Industry-standard ESD precautions should be used at all times.
Table 4. AAT3192 Electrical Specifications (1 of 2) (Note 1)
(VIN = VEN = 3.6 V, CIN = 1 µF, COUT = 1 µF, CCP = 1 µF, RSET = 14.3 kΩ, TA = –40 °C to 85 °C, [Typical Values are at TA = 25 °C], Unless
Otherwise Noted)
Parameter
Input voltage
Symbol
Test Condition
VIN
Input operating current
IIN
Input shutdown current
IIN(SHDN)
Min
Typical
2.7
Max
Units
5.5
V
EN/SET or EN/PWM = IN; VD1 = VD2 = IN
2.5
EN/SET or EN/PWM = IN; ID1= ID2 = FS,
VIN – VF = 1.5 V
2.5
Operating, ID1 = ID2 = FS, D1 and D2 = open
7.0
IN = 5.5 V; EN/SET or EN/PWM = GND
1
mA
µA
Charge Pump Section
Out maximum output current
IOUT
Charge pump oscillator frequency
fOSC
Charge pump mode hysteresis
VIN_(TH)
Output start-up time
100
0.65
mA
0.9
1.15
MHz
ID1= ID2 = 20 mA;
excluding AAT3192-4, PWM option
115
250
mV
tOUT
EN/SET or EN/PWM = IN
150
D1/D2 current accuracy
ID_(MAX)
DATA = 1; VIN – VF = 1.5 V
D1/D2 current matching
∆ID_(MAX)
DATA = 1; VIN – VF = 1.5 V
D1/D2 current accuracy (AAT3192-1 only)
ID_(DATA15)
DATA = 15; VIN – VF = 1.5 V
1.0
1.3
1.56
mA
D1/D2 current accuracy (AAT3192-2 only)
ID_(DATA8)
DATA = 8; VIN – VF = 1.5 V
1.0
1.3
1.56
mA
D1/D2 current accuracy (AAT3192-4 only)
ID_(10%)
Duty cycle = 10%; fPWM = 10 kHz;
VIN – VF = 1.5 V
2.4
mA
D1/D2 charge pump mode Transition
Threshold
VD_(TH)
ID1= ID2 = 20 mA
125
mV
µs
AAT3192-1/-2/-4: LED Current Sink Outputs
18
20
22
±3
mA
%
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Table 4. AAT3192 Electrical Specifications (2 of 2) (Note 1)
(VIN = VEN = 3.6 V, CIN = 1 µF, COUT = 1 µF, CCP = 1 µF, RSET = 14.3 kΩ, TA = -40 °C to 85 °C, [Typical Values are at TA = 25 °C], Unless
Otherwise Noted)
Parameter
Symbol
Test Condition
Min
18
Typical
Max
Units
20
22
mA
AAT3192-3: LED Current Sink Outputs
D1/D2 current accuracy
ID_(MAX)
RSET = 11.5 kΩ; DATA = 1; VIN – VF = 1.5 V
D1/D2 current matching
∆ID_(MAX)
RSET = 11.5 kΩ; DATA = 1; VIN – VF = 1.5 V
D1/D2 current accuracy
ID_(DATA4)
RSET = 11.5 kΩ; DATA = 4; VIN – VF = 1.5 V
D1/D2 charge pump mode transition
threshold
VD_(TH)
RSET = 11.5 kΩ; ID1= ID2 = 20 mA
±3
0.72
0.9
%
1.1
125
mA
mV
AAT3192-1/-2/-3: EN/SET and S2Cwire Control
EN input high threshold voltage
VENH
EN input low threshold voltage
VENL
1.4
EN input leakage current
IEN(LKG)
EN/SET input OFF timeout
tEN/SET(OFF)
500
µs
EN/SET input latch timeout
tEN/SET(LAT)
500
µs
EN/SET Input low time
tEN/SET(LOW)
75
µs
EN/SET minimum high time
tENSET(H-MIN)
EN/SET maximum high time
tENSET(H-MAX)
EN/SET = IN = 5 V
V
-1
0.3
0.4
V
1
µA
µs
50
75
µs
AAT3192-4: EN/PWM Current Control
EN/PWM input high threshold voltage
VENH
EN/PWM input low threshold voltage
VENL
EN/PWM input leakage current
IEN(LKG)
PWM control turn-on delay
tPWM(ON)
EN/PWM input OFF timeout
tEN/PWM
PWM control frequency
fPWM
1.4
EN/PWM = IN = 5 V
V
-1
0.4
V
1
µA
1
ms
50
kHz
µs
2
0.15
Duty cycle = 80%
Note 1: Performance is guaranteed only under the conditions listed in this Table.
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Typical Performance Characteristics
Figure 3. Operating Current (No Load) vs Input Voltage
Figure 4. Shutdown Current vs Temperature
Figure 5. Efficiency vs Input Current
Figure 6. Current Matching vs Temperature
Figure 7. 2X Mode Turn On (VIN = 3.6 V, 19.6 mA/ch)
Figure 8. 2X Mode Turn Off (VIN = 3.6 V, 19.6 mA/ch)
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Typical Performance Characteristics
Figure 9. 1X Mode Turn On (VIN = 4.2 V, 19.6 mA/ch)
Figure 10. Maximum LED Current vs RSET
Figure 11. EN Input High Threshold Voltage vs Input Voltage
Figure 12. EN Input Low Threshold Voltage vs Input Voltage
Figure 13. EN/SET Input Latch Timeout vs Input Voltage
Figure 14. EN/SET Input OFF Timeout vs Input Voltage
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Typical Performance Characteristics
Figure 15. Transition of LED Current (19.6 mA to 1.3 mA)
Figure 16. Transition of LED Current (1.3 mA to 19.6 mA)
Figure 17. Output Ripple Waveform (2X Mode; 20 mA Load)
Figure 18. Input Current vs Input Voltage
(Excluding AAT3192-4, PWM Option)
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Figure 19. AAT3192 Functional Block Diagram
Functional Description
Constant Current Control using RSET
The AAT3192 is a low cost charge-pump solution designed to
drive up to two white LEDs. The charge pump operates from a
2.7 V to 5.5 V power source and converts it to voltage levels
necessary to drive the LEDs.
The maximum current is programmed by an external resistor at
the RSET pin. Using a 14.3 kΩ external resistor at the RSET pin,
the AAT3192-1/-2/-4 includes an integrated serial LED current
control that sets the full-scale LED current between 20 mA and
0.63 mA. For the AAT3192-3, an 11.5 kΩ external resistor at
the RSET pin sets the full-scale LED current between 20 mA
and 1.3 mA. The full-scale LED current can set higher or lower
than 20 mA (see Tables 9 and 10). For maximum accuracy, a
1% tolerance resistor is recommended.
LED current is individually controlled through integrated current
sinks powered from the output of the charge pump. Low 1X
charge-pump output resistance and low-drop voltage current
sinks allow the charge pump to stay in 1X mode with an input
voltage as low as 3.75 V and LED forward voltages as high as
3.5 V. Once in 2X mode, the AAT3192-1/-2/-3 continuously
monitors the input supply voltage and automatically switch back
to 1X mode when there is sufficient input voltage. To support
fast PWM response, the 2X mode is latched in the AAT3192-4
and the device, once there, stays in that mode. To reset the
AAT3192-4 to the 1X mode, strobe EN/PWM low for 1 ms or
longer.
The AAT3192 requires only four external components: one 1 µF
ceramic capacitor for the charge pump flying capacitors (CP),
one 1 µF ceramic input capacitor (CIN), one 1 µF ceramic output
capacitor (COUT), and a resistor (RSET) to set the maximum LED
current. The AAT3192 can drive two constant output sinks (D1
and D2) with up to 30 mA maximum current each.
Skyworks S Cwire serial interface enables the AAT3192-1/-2/-3
and changes the current sink magnitudes through the EN/SET
pin. The AAT3192-4 uses an external PWM signal to enable the
device and to control the brightness of the LEDs.
2
S2Cwire Serial Interface (AAT3192-1/-2/-3 Only)
The LED output current of the AAT3192 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 I/C to manage LED or
display brightness, allowing the user to “set it and forget it.”
With its high-speed serial interface (1 MHz data rate), the LED
current can be changed quickly and easily. Also, the nonpulsating LED current reduces 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 (500 µs).
A functional block diagram is provided in Figure 19.
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
The programmed current is then seen at the current sink
outputs. When EN/SET is held low for an amount of time longer
than tOFF (500 µs), the AAT3192 enters into shutdown mode
and draws less than 1 µA from the input and the internal data
register is reset to zero. Figure 20 shows the S2C serial
interface timing.
The serial interface reduces the LED current on each rising
pulse of the enable input. If the AAT3192 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 5 and Figure 21 for the AAT3192-1. For the AAT3192-2,
Table 6 and Figure 22 illustrate an 8-step LED current control
profile. For the AAT3192-3, Table 7 and Figure 23 illustrate a 4step LED current control profile.
PWM Control (AAT3192-4 only)
PWM is an industry standard technique used to control LED
brightness by modulating the conduction duty cycle of the LED
current. LED brightness is determined by the average value of
the PWM signal multiplied by the LED’s intensity where intensity
is proportional to the LED drive current.
A PWM control signal can be applied to the EN/PWM pin of the
AAT3192-4. By changing the duty cycle of the PWM signal from
100% (logic high) to 10%, LEDs sink current can be
programmed from 20 mA to 2.4 mA. To save power when not
used, AAT3192-4 can be shut down by holding the EN/PWM pin
low for 1 ms.
Lastly, Table 8 and Figure 24 illustrate the AAT3192-4’s LED
current control profile as a function of a PWM control signal.
Figure 20. S2C Serial Interface Timing
Table 5. AAT3192-1 LED Current Settings
Data
EN Rising Edges
D1/D2 Current (mA)
1
1
20
2
2
18.7
3
3
17.3
4
4
16
5
5
14.7
6
6
13.3
7
7
12
8
8
10.7
9
9
9.3
10
10
8
11
11
6.7
12
12
5.3
13
13
4
14
14
2.7
15
15
1.3
16
16
0.63
Figure 21. AAT3192-1 Current Control Profile
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Table 6. AAT3192-2 LED Current Settings
Table 8. AAT3192-4 LED Current Settings
(RSET = 14.3 kΩ, fPWM = 50 kHz)
Data
EN Rising Edges
D1/D2 Current (mA)
1
1
20
EN/PWM Duty Cycle
2
2
17.3
100%
20
3
3
14.7
90%
17.9
4
4
12
80%
15.9
5
5
9.3
70%
14
6
6
6.7
60%
12.1
7
7
4
50%
10.1
8
8
1.3
40%
8.2
30%
6.3
20%
4.3
10%
2.4
D1/D2 Current (mA)
Figure 22. AAT3192-2 Current Control Profile
Table 7. AAT3192-3 LED Current Settings
Data
EN Rising Edges
D1/D2 Current (mA)
1
1
20
2
2
13.3
3
3
6.7
Application Information
4
4
0.87
LED Selection
Figure 24. AAT3192-4 Current Control Profile
(RSET = 14.3 kΩ, fPWM = 50 kHz)
The AAT3192 is specifically intended for driving white LEDs.
However, the device design allows the AAT3192 to drive most
types of LEDs with forward voltage specifications ranging from
2.2 V to 4.7 V. LED applications may include mixed
arrangements for display backlighting, keypad display, and any
other application needing a constant current sink generated
from a varying input voltage. Since the D1 to D2 constant
current sinks are matched with negligible supply voltage
dependence, the constant current channels are matched
regardless of the specific LED forward voltage (VF) levels.
Figure 23. AAT3192-3 Current Control Profile
The low dropout current sinks in the AAT3192 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.
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Constant Current Setting
Power Efficiency and Device Evaluation
The LED current is controlled by the RSET resistor. For maximum
accuracy, a 1% tolerance resistor is recommended. Table 9
shows RSET resistor values for AAT3192-1/2/4, and Table 10
shows RSET resistor values for AAT3192-3 for various LED fullscale current levels.
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
AAT3192, it is very difficult to measure efficiency in terms of a
percent value comparing input power over output power.
Table 9. Maximum LED Current and RSET Resistor Values
(1% Resistor Tolerance) for the AAT3192-1/2/4
ILED (mA)
RSET (kΩ)
30
9.53
25
11.5
20
14.3
18
15.8
15
19.1
10
28.7
Table 10. Maximum LED Current and RSET Resistor Values
(1% Resistor Tolerance) for the AAT3192-3
ILED (mA)
RSET (kΩ)
30
7.68
20
11.5
15
15.4
10
23.2
Device Switching Noise Performance
The AAT3192 operates at a fixed frequency of approximately
1 MHz to control noise and limit harmonics that can interfere
with the RF operation of mobile communication devices. Backinjected noise appearing on the input pin of the charge pump is
20 mV peak-to-peak, typically ten times less than inductorbased DC/DC boost converter white LED backlight solutions.
The AAT3192 soft-start feature prevents noise transient effects
associated with inrush currents during start-up of the charge
pump circuit.
Since the AAT3192 outputs are pure constant current sinks 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 is
maintained as a constant.
This makes quantifying output power a difficult task 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 percent efficiency.
The AAT3192 efficiency may be quantified under very specific
conditions and is dependent on the input voltage versus the
output voltage across the loads applied to outputs D1 through
D2 for a given constant current setting. Depending on the
combination of VIN and voltages sensed at the current sinks, the
device operates in load switch mode. When any one of the
voltages sensed at the current sinks nears dropout, the device
operates in 2X charge pump mode. Each of these modes yields
different efficiency values. Refer to the following two sections
for explanations for each operational mode.
1X Mode Efficiency
The AAT3192 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,
the voltage conversion efficiency is defined as output power
divided by input power.
An expression for the ideal efficiency (η) in 1X charge-pump
mode can be expressed as:
Shutdown
Since the current switches are the only power returns for all
loads, there is no leakage current when all sink switches are
disabled. To activate the shutdown operation, the EN/SET input
for the AAT3192-1/2/3 should be strobed low for longer than
tOFF (500 µs). For the 3192-4 PWM options, shutdown operation
is enabled when the EN/PWM input is strobed low longer than
1 ms. In this state, the AAT3192 typically draws less than 1 µA
from the input. Registers are reset to 0 in shutdown.
Or:
2X Charge Pump Mode Efficiency
The AAT3192 contains a charge pump which boosts 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
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
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.
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:
Or:
Figure 26. Lower Cost 1X Mode Application
Capacitor Selection
For a charge pump with an output of 5 V and a nominal input of
3.5 V, the theoretical efficiency is 71%. Due to internal
switching losses and IC quiescent current consumption, the
actual efficiency can be measured at 51%. The efficiency
decreases substantially as load current drops below 1 mA or
when the voltage level at VIN approaches the voltage level at
VOUT.
Additional Applications
The current sinks of the AAT3192 can be combined to drive
higher current levels through a single LED. As an example, a
single LED can be driven at 60 mA total by combining together
the D1 and D2 outputs, as shown in Figure 25.
Careful selection of the three external capacitors CIN, CP, and
COUT is important because they affect turn-on time, output
ripple, and transient performance. The optimum performance is
obtained when low Equivalent Series Resistance (ESR) ceramic
capacitors are used. In general, low ESR may be defined as less
than 100 mΩ. A value of 1μF for all four capacitors is a good
starting point when choosing capacitors. If the constant current
sinks 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 AAT3192. Ceramic
capacitors offer many advantages over their tantalum and
aluminum electrolytic counterparts. A ceramic capacitor
typically has very low ESR, is the 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)
Figure 25. Higher Current, Single LED Application
ESR is an important characteristic to consider when selecting a
capacitor. ESR is the internal resistance of 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.
For lower-cost applications, the flying capacitor can be removed,
as shown in Figure 26. This forces the AAT3192 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.
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Ceramic Capacitor Materials
Evaluation Board Description
Ceramic capacitors less than 0.1 µF 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
2.2 µF) are often available in low cost Y5V and Z5U dielectrics,
but capacitors larger than 1 µF are not typically required for the
AAT3192 applications.
The AAT3192 Evaluation Board schematic diagram is provided
in Figure 27. The PCB layer details are shown in Figure 28.
Package Information
Package dimensions for the SC70JW-10 are shown in Figure 29,
and tape and reel dimensions are provided in Figure 30.
Capacitor area is another contributor to ESR. The capacitor that
is physically large has a lower ESR when compared to a smaller
capacitor with same material. These larger devices can improve
circuit transient response when compared to an equal value
capacitor in a smaller package size.
Figure 27. AAT3192 Evaluation Board Schematic
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Figure 28. AAT3192 Evaluation Board Layout
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Figure 29. AAT3192 SC70JW-10 Package Dimensions
Figure 30. AAT3192 Tape and Reel Dimensions
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DATA SHEET • AAT3192 TWO-CHANNEL CHARGE PUMP LED DRIVER
Ordering Information
Model Name
Manufacturing Part Number (Note 1)
AAT3192 Two-Channel Charge Pump LED Driver
Evaluation Board Part Number
S Cwire
16-step
AAT3192IJQ-1-T1
AAT3192IJQ-1-T1-EVB
S2Cwire
8-step
AAT3192IJQ-2-T1
AAT3192IJQ-2-T1-EVB
S2Cwire
4-step
AAT3192IJQ-3-T1
AAT3192IJQ-3-T1-EVB
PWM
Linear
AAT3192IJQ-4-T1
AAT3192IJQ-4-T1-EVB
2
Note 1: Sample stock is generally held on part numbers listed in BOLD.
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