AAT3169IFO-T1 [AAT]

High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications; 高效率1X / 1.5X / 2X电荷泵白光LED应用
AAT3169IFO-T1
型号: AAT3169IFO-T1
厂家: ADVANCED ANALOG TECHNOLOGY, INC.    ADVANCED ANALOG TECHNOLOGY, INC.
描述:

High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications
高效率1X / 1.5X / 2X电荷泵白光LED应用

文件: 总14页 (文件大小:438K)
中文:  中文翻译
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AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
ChargePump  
General Description  
Features  
The AAT3169 is a low noise, constant frequency  
charge pump DC/DC converter that uses a tri-mode  
load switch (1X), fractional (1.5X), and doubling  
(2X) conversion to maximize efficiency for white  
LED applications. The AAT3169 is capable of driv-  
ing six LEDs for a total of 180mA from a 2.7V to  
5.5V input. The current sinks may be operated indi-  
vidually or in parallel for driving higher current LEDs.  
A low external parts count (two 1µF flying capacitors  
and two small 1µF capacitors at IN and OUTCP)  
make this part ideally suited for small, battery-pow-  
ered applications.  
VIN Range: 2.7V to 5.5V  
Fully Programmable Current with Single Wire  
— 16-Step Logarithmic Scale  
— 15/20/30mA Max Current  
— Four Low-Current Settings Down to 115µA  
— Low IQ (65µA) for Single-Channel, Low-  
Current Mode  
Tri-Mode 1X, 1.5X, and 2X Charge Pump for  
Maximum Efficiency and VF Coverage  
Drives Up to Six LEDs  
Individual Main-Sub (5-1) Group Control  
No Inductors, Low Noise Operation  
1MHz Constant Switching Frequency  
Small Application Circuit  
Built-In Thermal Protection  
Built-In Auto-Disable for Open Circuit  
Automatic Soft Start  
IQ <1µA in Shutdown  
Thermally-Enhanced STDFN33-14 or  
QFN44-16 Package  
AnalogicTech's AS2Cwire™ (Advanced Simple Serial  
Control™) serial digital input is used to enable, dis-  
able, and set current for each LED with a 16-level  
logarithmic scale plus four low-current settings down  
to 115µA. For optimized efficiency, low-current set-  
tings require only 65µA of housekeeping current.  
Each output of the AAT3169 is equipped with built-  
in protection for output short-circuit and auto-dis-  
able for load short-circuit conditions. Built-in soft-  
start circuitry prevents excessive inrush current  
during start-up. A low-current shutdown feature dis-  
connects the load from the input and reduces qui-  
escent current to less than 1µA.  
Applications  
Color (RGB) Lighting  
Programmable Current Sink  
Transmissive Displays  
White LED Backlighting  
White Photo Flash for Digital Still Cameras  
The AAT3169 is available in a Pb-free, space-sav-  
ing, thermally-enhanced 16-pin 4x4mm QFN pack-  
age or a low-profile 14-pin 3x3mm STDFN pack-  
age and is rated over the -40°C to +85°C tempera-  
ture range.  
Typical Application  
C1+  
C1-  
C2+  
C1  
1µF  
C2  
1µF  
Main  
Sub  
D6  
C2-  
OUTCP  
COUT  
1µF  
IN  
2.7V to 5.5V  
CIN  
1µF  
D1  
D2  
D3  
D4  
D5  
AAT3169  
D1  
D2  
D3  
D4  
D5  
D6  
EN/SET  
EN/SET  
3169.2006.08.1.2  
1
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
Pin Descriptions  
Pin #  
AAT3169ISN AAT3169IFP  
Symbol  
Function  
1
2
3
4
2
3
D6  
Current sink input #6.  
AS2Cwire serial interface control pin.  
EN/SET  
N/C  
n/a  
6
No connection.  
OUTCP  
Charge pump output to drive load circuit. Requires 1µF capacitor con-  
nected between this pin and ground.  
5
6
7
4
C2+  
C1+  
Flying capacitor 2 positive terminal. Connect a 1µF capacitor between  
C2+ and C2-.  
Flying capacitor 1 positive terminal. Connect a 1µF capacitor between  
C1+ and C1-.  
7
8
5
8
C1-  
C2-  
GND  
IN  
Flying capacitor 1 negative terminal.  
Flying capacitor 2 negative terminal.  
9, 11  
10  
10  
9
Ground.  
Input power supply. Requires 1µF capacitor connected between this pin  
and ground.  
12  
13  
14  
15  
16  
EP  
11  
12  
13  
14  
1
D1  
D2  
D3  
D4  
D5  
Current sink input #1.  
Current sink input #2.  
Current sink input #3.  
Current sink input #4.  
Current sink input #5.  
n/a  
Exposed paddle (bottom); connect to ground as closely as possible to  
the package.  
Pin Configuration  
QFN44-16  
(Top View)  
STDFN33-14  
(Top View)  
1
2
14  
13  
D5  
D6  
EN/SET  
C1+  
C1-  
D4  
D3  
D2  
D1  
GND  
IN  
C2-  
1
2
3
4
12  
11  
10  
9
D6  
EN/SET  
N/C  
D1  
3
4
5
6
7
12  
11  
10  
9
GND  
IN  
OUTCP  
C2+  
8
OUTCP  
GND  
2
3169.2006.08.1.2  
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
Absolute Maximum Ratings1  
Symbol  
Description  
Value  
Units  
VIN  
Input Voltage to GND  
-0.3 to 6  
-0.3 to VIN + 0.3  
210  
V
V
VEN/SET  
EN/SET Voltage to GND  
2
IOUT  
Maximum DC Output Current  
mA  
°C  
°C  
TJ  
Operating Junction Temperature Range  
Maximum Soldering Temperature (at leads, 10 sec)  
-40 to 150  
300  
TLEAD  
Thermal Information3  
Symbol  
Description  
Value  
Units  
QFN44-164  
STDFN33-144  
QFN44-16  
PD  
Maximum Power Dissipation  
2.0  
W
θJA  
Maximum Thermal Resistance  
50  
°C/W  
STDFN33-14  
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.  
4. Derate 20mW/°C above 25°C.  
3169.2006.08.1.2  
3
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
Electrical Characteristics1  
CIN = COUT = C1 = C2 = 1.0µF; TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C,  
VIN = 3.6V.  
Symbol Description  
Input Power Supply  
Conditions  
Min Typ Max Units  
VIN  
Operation Range  
2.7  
5.5  
V
1X Mode, 3.0 VIN 5.5, Active,  
No Load Current, High Current Mode  
1.5X Mode, 3.0 VIN 5.5, Active,  
No Load Current, High Current Mode  
2X Mode, 3.0 VIN 5.5, Active,  
No Load Current, High Current Mode  
1X Mode, 3.0 VIN 5.5, D6 Active,  
No Load Current, Low Current Mode  
VEN/SET = 0V  
0.3  
1
mA  
ICC  
Operating Current  
1
65  
90  
µA  
µA  
ISHDN  
IDX  
Shutdown Current  
Current Accuracy  
1
I
SET = 20mA, TA = 25°C  
-10  
-20  
-20  
10  
20  
20  
1
ISET = 2.4mA, TA = 25°C  
ISET = 400µA, TA = 25°C  
VF:D1:D6 = 3.6V  
%
Low Current Accuracy  
Current Matching2  
I(D-Match)  
VTH  
0.5  
%
1X to 1.5X or 1.5X to 2X Transition  
Threshold at Any ISINK Pin  
ISET = 20mA  
150  
mV  
Charge Pump Section  
TSS  
FCLK  
Soft-Start Time  
100  
µs  
Clock Frequency  
1000  
kHz  
EN/SET  
VEN(L)  
Enable Threshold Low  
Enable Threshold High  
VIN = 2.7V  
VIN = 5.5V  
0.4  
75  
V
V
VEN(H)  
1.4  
0.3  
TEN/SET LO EN/SET Low Time  
µs  
ns  
µs  
µs  
µs  
µA  
TEN/SET HI MIN Minimum EN/SET High Time  
50  
_
_
TEN/SET HI MAX Maximum EN/SET High Time  
75  
500  
500  
1
_
_
TOFF  
TLAT  
EN/SET Off Timeout  
EN/SET Latch Timeout  
EN/SET Input Leakage  
IEN/SET  
-1  
1. The AAT3169 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.  
2. Current matching is defined as the deviation of any sink current from the average of all active channels.  
4
3169.2006.08.1.2  
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
Typical Characteristics  
CIN = COUT = C1 = C2 = 1.0µF, VIN = 3.6V, TA = 25°C, unless otherwise noted.  
Turn-On to 1X Mode  
(VIN = 4.2V; 20mA/Channel)  
Efficiency vs. Supply Voltage  
100  
4.9mA/ch  
VF = 2.9V  
10.9mA/ch  
VF = 3.1V  
20mA/ch  
VF = 3.4V  
EN  
(2V/div)  
90  
80  
70  
60  
50  
CP  
(2V/div)  
VSINK  
(500mV/div)  
IIN  
(200mA/div)  
2.8  
3.0  
3.2  
3.4  
3.6  
3.8  
4.0  
4.2  
Time (100µs/div)  
Supply Voltage (V)  
Turn-On to 1.5X Mode  
(VIN = 3.8V; 20mA/Channel)  
Turn-On to 2X Mode  
(VIN = 2.8V; 20mA/Channel)  
EN  
(2V/div)  
EN  
(2V/div)  
CP  
(2V/div)  
CP  
(2V/div)  
VSINK  
(500mV/div)  
VSINK  
(500mV/div)  
IIN  
(200mA/div)  
IIN  
(200mA/div)  
Time (100µs/div)  
Time (100µs/div)  
Turn-Off from 1.5X Mode  
(VIN = 3.5V; 20mA/Channel)  
Current Matching vs. Temperature  
20.2  
20.0  
19.8  
19.6  
19.4  
19.2  
Channel 1  
Channel 2  
EN  
(2V/div)  
Channel 5  
VF  
(1V/div)  
Channel 3  
IIN  
(100mA/div)  
Channel 4  
Channel 6  
60  
-40  
-20  
0
20  
40  
80  
Time (100µs/div)  
Temperature (°°C)  
3169.2006.08.1.2  
5
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
Typical Characteristics  
CIN = COUT = C1 = C2 = 1.0µF, VIN = 3.6V, TA = 25°C, unless otherwise noted.  
Load Characteristics  
(VIN = 3.8V; 1.5X Mode; 15mA/Channel)  
Load Characteristics  
(VIN = 2.9V; 2X Mode; 15mA/Channel)  
VIN  
(40mV/div)  
VIN  
(40mV/div)  
CP  
(40mV/div)  
CP  
(40mV/div)  
VSINK  
(40mV/div)  
VSINK  
(40mV/div)  
Time (500ns/div)  
Time (500ns/div)  
Load Characteristics  
(VIN = 4.0V; 1.5X Mode; 20mA/Channel)  
Load Characteristics  
(VIN = 3.1V; 2X Mode; 20mA/Channel)  
VIN  
(40mV/div)  
VIN  
(40mV/div)  
CP  
(40mV/div)  
CP  
(40mV/div)  
VSINK  
(40mV/div)  
VSINK  
(40mV/div)  
Time (500ns/div)  
Time (500ns/div)  
Load Characteristics  
(VIN = 4.3V; 1.5X Mode; 30mA/Channel)  
Load Characteristics  
(VIN = 3.6V; 2X Mode; 30mA/Channel)  
VIN  
(40mV/div)  
VIN  
(40mV/div)  
CP  
(40mV/div)  
CP  
(40mV/div)  
VSINK  
(40mV/div)  
VSINK  
(40mV/div)  
Time (500ns/div)  
Time (500ns/div)  
6
3169.2006.08.1.2  
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
Typical Characteristics  
CIN = COUT = C1 = C2 = 1.0µF, VIN = 3.6V, TA = 25°C, unless otherwise noted.  
TLAT vs. VIN  
TOFF vs. VIN  
350  
300  
250  
200  
150  
100  
50  
400  
350  
300  
250  
200  
150  
100  
50  
-40°C  
-40°C  
85°C  
25°C  
25°C  
85°C  
0
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  
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  
VIN (V)  
VIN (V)  
VIH vs. VIN  
Input Ripple vs. VIN  
1.2  
1.1  
1
25  
20  
15  
10  
5
-40°C  
30mA/ch  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
25°C  
85°C  
20mA/ch  
10.9mA/ch  
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  
2.50 2.67 2.84 3.01 3.18 3.35 3.52 3.69 3.86 4.03 4.20  
VIN (V)  
VIN (V)  
VIL vs. VIN  
1.2  
1.1  
1
-40°C  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
25°C  
85°C  
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  
VIN (V)  
3169.2006.08.1.2  
7
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
Functional Block Diagram  
C1+ C1- C2+ C2-  
1X, 1.5X, 2X  
Charge Pump  
IN  
OUTCP  
Soft-Start  
Control  
1MHz  
Oscillator  
Voltage  
Reference  
D1  
D/A  
D/A  
D/A  
D/A  
D/A  
D2  
D3  
D4  
D5  
Main  
6 x 16 Bit  
ROM  
AS2Cwire  
EN/SET  
Interface  
Sub  
6 x 16 Bit  
ROM  
D/A  
D6  
GND  
The six constant current sink inputs (D1 to D6) can  
drive six individual LEDs with a maximum current  
of 30mA nominal each. Unused sink inputs should  
be connected to OUTCP, otherwise the part will  
operate only in 2X charge pump mode. The  
AS2Cwire serial interface enables the AAT3169 and  
sets the current sink magnitudes. AS2Cwire  
addressing allows independent control of two  
groups of current sink input: D1~D5 and D6.  
Functional Description  
The AAT3169 is a tri-mode load switch (1X) and  
high efficiency (1.5X or 2X) charge pump device  
intended for white LED backlight applications. To  
maximize power conversion efficiency, an internal  
sensing circuit monitors the voltage required on  
each constant current sink input and sets the load  
switch and charge pump modes based on the input  
battery voltage and the current sink input voltage.  
As the battery discharges over time, the AAT3169  
charge pump is enabled when any of the six current  
sink inputs near dropout. The charge pump initially  
starts in 1.5X mode. If the charge pump output  
droops enough for any current source output to  
become close to dropout, the charge pump will  
automatically transition to 2X mode. The AAT3169  
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  
charge pump output capacitor (COUT).  
Constant Current Output Level Settings  
The constant current sink levels for D1 to D6 are  
set via the serial interface according to a logarith-  
mic scale where each code is approximately 1.8dB  
lower than the previous code. In this manner, LED  
brightness appears linear with each increasing  
code count. Because the inputs D1 to D6 are true  
independent constant current sinks, the voltage  
observed on any single given input will be deter-  
mined by the actual forward voltage (VF) for the  
LED being driven.  
8
3169.2006.08.1.2  
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
AS2Cwire Serial Interface  
Since the input current sinks of the AAT3169 are  
programmable, no PWM (pulse width modulation)  
or additional control circuitry is needed to control  
LED brightness. This feature greatly reduces the  
burden on a microcontroller or system IC to man-  
age LED or display brightness, allowing the user to  
"set it and forget it." With its high-speed serial inter-  
face (1MHz data rate), the input sink current of the  
AAT3169 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.  
The current sink input magnitude on the AAT3169  
is controlled by AnalogicTech's Advanced Simple  
Serial Control (AS2Cwire) serial digital input.  
AS2Cwire adds addressing capability for multiple  
data registers over the Simple Serial Control™  
(S2Cwire™), which is only capable of controlling a  
single register. The AAT3169 has four registers:  
Bank1, Bank2, Max Current, and Low Current.  
Three addresses are used to control the two regis-  
ters. Address 0 addresses both registers simulta-  
neously to allow the loading of both registers with  
the same data using a single write protocol.  
Address 1 addresses Register 1 for D1 to D5 cur-  
rent level settings. Address 2 addresses Register 2  
for D6 current level settings.  
The 16 individual current level settings are each  
approximately 1.8dB apart (see Table 1). Code 1 is  
full scale; Code 15 is full scale attenuated by  
approximately 25dB; and Code 16 is reserved as a  
"no current" setting.  
AS2Cwire relies on the number of rising edges of  
the EN/SET pin to address and load the registers.  
AS2Cwire latches data or address after the EN/SET  
pin has been held high for time TLAT. Address or  
data is differentiated by the number of EN/SET ris-  
ing edges. Since the data registers are 4 bits each,  
the differentiating number of pulses is 24 or 16, so  
that Address 0 is signified by 17 rising edges,  
Address 1 by 18 rising edges, and Address 2 by 19  
rising edges. Data is set to any number of rising  
edges between 1 and including 16. A typical write  
protocol is a burst of EN/SET rising edges, signify-  
ing a particular address, followed by a pause with  
EN/SET held high for the TLAT timeout period, a  
burst of rising edges signifying data, and a TLAT  
timeout for the data registers. Once an address is  
set, then multiple writes consisting of data only  
(without address) to the corresponding data regis-  
ter are allowed. Address 0 is the default address  
on the first rising edge after the AAT3169 has been  
disabled. If data is presented on the first rising  
edge with no prior address, both data registers are  
simultaneously loaded.  
Mean  
Mean  
Mean  
Data 30mA Max 20mA Max 15mA Max  
1
2
30.0  
29.3  
27.8  
25.2  
22.8  
20.9  
18.5  
16.1  
13.7  
10.0  
9.4  
20.0  
19.5  
18.5  
17.5  
15.4  
14.2  
12.5  
10.9  
9.3  
15.0  
14.6  
13.9  
12.7  
11.5  
10.5  
9.3  
3
4
5
6
7
8
8.1  
9
7.0  
10  
11  
12  
13  
14  
15  
16  
8.0  
6.0  
6.5  
4.9  
7.0  
4.9  
3.7  
4.7  
3.3  
2.6  
3.3  
2.4  
1.9  
1.9  
1.5  
1.2  
0.0  
0.0  
0.0  
Table 1: Mean Table of AAT3169 Output Current.  
3169.2006.08.1.2  
9
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
The maximum current level is determined by the  
value set in Register 3, the Max Current register.  
Three scales are available for high operating cur-  
rents with maximum current levels of 30mA, 20mA,  
or 15mA. Each scale maintains approximately  
1.8dB steps between settings. A separate mode is  
available for ultra-low LED current operation.  
When the Max Current register (Register 3) is set  
to the Low Current setting, the Low Current regis-  
ter (Register 4) must be programmed. The two  
most significant bits of the Low Current register  
control whether or not a given bank of current sinks  
is enabled. The least two significant bits of the Low  
Current register sets the current level for both  
banks. For low current settings, the charge pump  
may be enabled if required by the battery voltage  
and LED forward voltage conditions, and 1X mode  
quiescent current is approximately 130µA for multi-  
ple channels or 65µA for Channel 6 operation only.  
Both banks of current sinks must be in the same  
high or low current mode of operation.  
Low Current Register (Address 4)  
Main Low  
Sub Low  
Data  
Current On Current On Current  
1
2
No  
No  
No  
No  
3
No  
No  
4
No  
No  
5
No  
Yes  
Yes  
Yes  
Yes  
No  
115µA  
175µA  
280µA  
400µA  
115µA  
175µA  
280µA  
400µA  
115µA  
175µA  
280µA  
400µA  
6
No  
7
No  
8
No  
9
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
10  
11  
12  
13  
14  
15  
16  
No  
No  
No  
Yes  
Yes  
Yes  
Yes  
When EN/SET is held low for an amount of time  
greater than TOFF, the AAT3169 enters shutdown  
mode and draws less than 1µA from the input.  
Data and Address registers are reset to 0 during  
shutdown.  
Auto-Disable Feature  
AAT3169 is equipped with an auto-disable feature  
for each LED channel. After the IC is enabled and  
started up, a test current of 120µA (typical) is  
forced through each sink channel. The channel will  
be disabled if the voltage of that particular SINK pin  
does not drop to a certain threshold. This feature is  
very convenient for disabling an unused channel or  
during an LED fail-short event.  
AS2Cwire Serial Interface Addressing  
EN/SET  
Address Rising Edges  
Data Register  
AAT3169  
0
1
2
3
4
17  
18  
19  
20  
21  
1&2: D1~D6 Current  
1: D1~D5 Current  
2: D6 Current  
Thermal Protection  
The AAT3169 has a built-in thermal protection cir-  
cuit that will shut down the charge pump if the die  
temperature rises above the thermal limit, as would  
be the case during a short circuit of the OUTCP pin.  
3: Max Current  
4: Low Current  
Data  
Max Current  
1
2
3
4
20mA  
30mA  
15mA  
Low Current  
(see Low Current Register for values)  
10  
3169.2006.08.1.2  
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
AS2Cwire Serial Interface Timing  
Address  
Data  
THI  
TLAT  
TLO  
TLAT  
EN/SET  
Address  
1
2
17  
18  
1
2 . . .  
n <= 16  
0
1
0
0
n
Data Reg 1  
Data Reg 2  
Device Switching Noise Performance  
Applications Information  
The AAT3169 operates at a fixed frequency of  
approximately 1MHz to control noise and limit har-  
monics that can interfere with the RF operation of  
cellular telephone handsets or other communica-  
tion 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 solu-  
tions. The AAT3169 soft-start feature prevents  
noise transient effects associated with inrush cur-  
rents during start-up of the charge pump circuit.  
LED Selection  
Although the AAT3169 is designed for driving white  
LEDs, the device also can be used to drive most  
types of LEDs with forward voltages from 2.0V to  
4.7V. 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 vary-  
ing input voltage. Since the D1 to D6 input current  
sinks are matched with negligible voltage depend-  
ence, the LED brightness will be matched regard-  
less of the specific LED forward voltage (VF) levels.  
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 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 LED current sources are programmed only  
for light current levels, then the capacitor size may  
be decreased.  
In some instances (e.g., in high luminous output  
applications such as photo flash), it may be neces-  
sary to drive high-VF type LEDs. The low dropout  
current sinks in the AAT3169 make it capable of  
driving LEDs with forward voltages as high as 4.7V  
at full current from an input supply as low as 3.0V.  
Outputs can be paralleled to drive high-current  
LEDs without complication.  
3169.2006.08.1.2  
11  
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
Capacitor Characteristics  
Ceramic Capacitor Materials  
Ceramic composition capacitors are highly recom-  
mended over all other types of capacitors for use  
with the AAT3169. Ceramic capacitors offer many  
advantages over their tantalum and aluminum elec-  
trolytic counterparts. A ceramic capacitor typically  
has very low equivalent series resistance (ESR), is  
lowest cost, has a smaller PCB footprint, and is  
non-polarized. Low ESR ceramic capacitors help  
maximize charge pump transient response. Since  
ceramic capacitors are non-polarized, they are not  
prone to incorrect connection damage.  
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 val-  
ues are usually composed of X7R, X5R, Z5U, or  
Y5V dielectric materials. Large ceramic capacitors  
(i.e., greater than 2.2µF) are often available in low-  
cost Y5V and Z5U dielectrics, but capacitors  
greater than 1µF are not typically required for  
AAT3169 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.  
Equivalent Series Resistance  
ESR is an important characteristic to consider when  
selecting a capacitor. ESR is resistance internal to  
a capacitor that is caused by the leads, internal con-  
nections, 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.  
12  
3169.2006.08.1.2  
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
Ordering Information  
Package  
Marking1  
Part Number (Tape and Reel)2  
STDFN33-14  
QFN44-16  
UNXYY  
RVXYY  
AAT3169IFO-T1  
AAT3169ISN-T1  
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means  
semiconductor products that are in compliance with current RoHS standards, including  
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more  
information, please visit our website at http://www.analogictech.com/pbfree.  
Package Information  
STDFN33-14  
Detail "A"  
Index Area  
(D/2 x E/2)  
1.70 0.05  
3.00 0.05  
Top View  
Bottom View  
0.425 0.05  
0.05 0.05  
Side View  
Detail "A"  
All dimensions in millimeters.  
1. XYY = assembly and date code.  
2. Sample stock is generally held on part numbers listed in BOLD.  
3169.2006.08.1.2  
13  
AAT3169  
High Efficiency 1X/1.5X/2X Charge  
Pump for White LED Applications  
QFN44-16  
Pin 1 Identification  
0.330 0.050  
13  
Pin 1 Dot By Marking  
16  
1
4
R0.030Max  
9
8
5
4.000 0.050  
2.280 REF  
Top View  
Bottom View  
0.203 0.025  
Side View  
All dimensions in millimeters.  
© Advanced Analogic Technologies, Inc.  
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights,  
or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice.  
Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold sub-  
ject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech  
warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality con-  
trol techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.  
AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are regis-  
tered trademarks or trademarks of their respective holders.  
Advanced Analogic Technologies, Inc.  
830 E. Arques Avenue, Sunnyvale, CA 94085  
Phone (408) 737-4600  
Fax (408) 737-4611  
14  
3169.2006.08.1.2  

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