AAT2860IMK-3-T1 [ANALOGICTECH]
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit; 背光/闪光LED驱动器和多个LDO照明管理单元
| 型号： | AAT2860IMK-3-T1 |
| 厂家： | 
ADVANCED ANALOGIC TECHNOLOGIES |
| 描述： | Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit |
| 文件： | 总23页 (文件大小：2894K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
General Description
Features
•
•
•
The AAT2860-x is a highly integrated charge pump-based
lighting management unit (LMU) with three low dropout
(LDO) regulators optimized for single-cell lithium-ion/
polymer systems. The charge pump provides power for
all LED outputs; multiple backlight and flash LED configu-
rations are available. The backlight LED outputs can be
programmed up to 31mA each and the flash LED outputs
can be programmed up to 300mA each. An I2C compati-
ble serial digital interface is used to enable, disable, and
set the current to one of 32 levels for the backlight and
one of 16 levels for the flash. A programmable safety
timer and flash control input is included for easy flash
control. Backlight current matching is better than 3% for
uniform display brightness, and flash current matching is
better than 5% for uniform power dissipation.
Input Voltage Range: 2.7V to 5.5V
I2C Compatible Serial Interface
Tri-Mode Charge Pump
Drives up to Seven LEDs (Backlight/Flash)
Programmable Backlight Current Settings
▪
•
•
32 Levels - 0.5mA to 31mA
Programmable Flash Current
▪
16 Levels – OFF to 300mA
1MHz Switching Frequency
Automatic Soft-Start
▪
•
•
•
Three Low Dropout Regulators
300mA Output Current
150mV Dropout
Programmable Output from 1.5V to 3.0V
Output Auto-Discharge for Fast Shutdown
▪
▪
▪
▪
•
•
•
Built-In Thermal Protection
-40°C to +85°C Temperature Range
TQFN34-24 Package
The AAT2860-x offers three high-performance low-noise
MicroPower™ LDO linear regulators. The regulators are
enabled and their output voltages are set through the
I2C compatible serial interface. Each LDO can supply up
to 300mA load current and ground-pin current is only
80µA making the AAT2860-x ideal for battery-operated
applications.
Applications
•
•
•
Camera Enabled Mobile Devices
Digital Still Cameras
Multimedia Mobile Phones
The AAT2860-x is available in a Pb-free, space saving
TQFN34-24 package and operates over the -40°C to
+85°C ambient temperature range.
Typical Application
C1
1µF
C2
1µF
WLEDs
OSRAM LW M673
or equivalent
C1+ C1- C2+ C2-
VOUT
IN
OUT
Flash LEDs
Lumiled LXCL-PWF1
or equivalent
VBAT
3.6V
CIN
4.7µF
COUT
2.2µF
AAT2860-x
IN
BL1
CIN
4.7µF
BL2
LED Select
LED_SEL
BL3
BL4
BL5
FL_LVL
SDA
Flash Level Select
BL6/FL1
BL7/FL2
SDA
I2C Serial
Interface
VLDOA
at 300mA
LDOA
SCL
SCL
CLDOA
2.2µF
VLDOB
at 300mA
LDOB
LDO Select
LDO_SEL
CLDOB
2.2µF
VLDOC
LDOC
PGND
at 300mA
AGND
CLDOC
2.2µF
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2860.2008.05.1.0
1
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Pin Descriptions
Pin # Symbol Description
Charge pump output. OUT is the output of the charge pump and supplies current to the backlight and flash
LEDs. Connect the backlight and flash LED anodes to OUT. Bypass OUT to PGND with a 2.2μF or larger ceramic
1
OUT
capacitor as close to the AAT2860-x as possible.
2
3
4
C2+
SDA
SCL
Positive terminal of charge pump capacitor 2. Connect the 1μF charge pump capacitor 2 from C2+ to C2-.
I2C compatible serial data input. SDA is the data input of the I2C serial interface. Drive SDA with the I2C data.
I2C compatible serial clock input. SCL is the clock input of the I2C serial interface. Drive SCL with the I2C clock.
LED Programming Enable Input. When LED_SEL is strobed low-to-high, the backlight and flash LED registers
can be programmed via the I2C compatible serial interface. When LED_SEL is strobed high-to-low, all backlight
and flash LED outputs are turned off and the backlight and flash LED registers are reset to their default (power-
on-reset or POR) values.
5
LED_SEL
AAT2860-2/3/4: Flash/Torch enable input. When LED_SEL is strobed high and FL_LVL is strobed high, the flash
LED current outputs are enabled and set according to the contents of the flash LED current register. When
FL_LVL is strobed high-to-low, the flash LED outputs return to their low-level programmed values.
AAT2860-1/5: Connect to AGND.
FL_LVL
(AGND)
6
7
Programming enable input for LDO[A, B, C]. When LDO_SEL is strobed low-to-high, the LDO output voltages can
LDO_SEL be programmed via the I2C compatible serial interface. Strobing LDO_SEL high-to-low resets the contents of the
LDO output voltage registers to their default (POR) values and forces all outputs to 0 (zero) volt.
8
9
AGND
Analog ground. Connect AGND to PGND at a single point as close to the AAT2860-x as possible.
LDOC regulated voltage output. LDOC is the voltage output of LDOC. Bypass LDOC to AGND with a 2.2μF or
larger ceramic capacitor as close to the AAT2860-x as possible.
LDOC
LDOB regulated voltage output. LDOB is the voltage output of LDOB. Bypass LDOB to AGND with a 2.2μF or
larger ceramic capacitor as close to the AAT2860-x as possible.
Input power pin for all three LDOs. Connect Pin 11 to Pin 23 with as short a PCB trace as practical. Bypassing
this pin with a separate 4.7µF or larger ceramic capacitor will improve performance.
LDOA regulated voltage output. LDOA is the voltage output of LDOA. Bypass LDOA to AGND with a 2.2μF or
larger ceramic capacitor as close to the AAT2860-x as possible.
Backlight LED 1 current sink/channel. BL1 controls the current through backlight LED 1. Connect the cathode of
backlight LED 1 to BL1. If not used, connect BL1 to OUT.
Backlight LED 2 current sink/channel. BL2 controls the current through backlight LED 2. Connect the cathode of
backlight LED 2 to BL2. If not used, connect BL2 to OUT.
Backlight LED 3 current sink/channel. BL3 controls the current through backlight LED 3. Connect the cathode of
backlight LED 3 to BL3. If not used, connect BL3 to OUT.
10
11
12
13
14
15
16
17
LDOB
IN
LDOA
BL1
BL2
BL3
BL4
BL5
Backlight LED 4 current sink/channel. BL4 controls the current through backlight LED 4. Connect the cathode of
backlight LED 4 to BL4. If not used, connect BL4 to OUT.
Backlight LED 5 current sink/channel. BL5 controls the current through backlight LED 5. Connect the cathode of
backlight LED 5 to BL5. If not used, connect BL5 to OUT.
AAT2860-1/2/3/5/6: Backlight LED 6 current sink/channel. BL6 controls the current through backlight LED 6.
Connect the cathode of backlight LED 6 to BL6. If not used, connect BL6 to OUT.
AAT2860-4: Flash LED 1 current sink. FL1 controls the current through Flash LED 1. Connect the cathode of
Flash LED 1 to FL1. If not used, connect FL1 to OUT.
AAT2860-1/5/6: Backlight LED 7 current sink/channel. BL7 controls the current through backlight LED 7. Con-
nect the cathode of backlight LED 7 to BL7. If not used, connect BL7 to OUT.
AAT2860-2/3/4: Flash LED or Flash LED 2 current sink. FL2 controls the current through Flash LED 2. Connect
the cathode of Flash LED 2 to FL2. If not used, connect FL2 to OUT.
BL6
(FL1)
18
19
BL7
(FL2)
20
21
22
PGND
C2-
C1-
Power ground. Connect PGND to AGND at a single point as close to the AAT2860-x as possible.
Negative terminal of charge pump capacitor 2.
Negative terminal of charge pump capacitor 1.
Power input. Connect IN to the input source voltage. Bypass IN to PGND with a 4.7μF or larger ceramic capacitor
as close to the AAT2860-x as possible.
23
IN
24
EP
C1+
Positive terminal of charge pump capacitor 1. Connect the 1μF charge pump capacitor 1 from C1+ to C1-.
Exposed paddle (bottom) Connect to PGND/AGND as close to the AAT2860-x as possible.
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2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Pin Configuration
TQFN34-24
(Top View)
24
23
22
21
20
19
18
17
16
15
14
13
1
2
OUT
C2+
SDA
BL7/FL2
BL6/FL1
BL5
BL4
BL3
3
4
5
SCL
LED_SEL
FL_LVL
LDO_SEL
6
7
BL2
BL1
8
9
10
11
12
Part Number Descriptions1
Backlight LED Outputs
Part Number
Main
Sub
Flash LED Outputs
AAT2860-1
AAT2860-2
AAT2860-3
AAT2860-4
AAT2860-5
AAT2860-6
7/4
6/4
6/5
5/4
7/6
7/5
0/3
0/2
0/1
0/1
0/1
0/2
0
1
1
2
0
0
Absolute Maximum Ratings2
Symbol Description
Value
Units
IN, OUT, BL1, BL2, BL3, BL4, BL5, BL6/FL1, BL7/FL2 Voltage to AGND
C1+, C2+, SDA, SCL Voltage to AGND
LDOA, LDOB, LDOC, LED_SEL, FL_LVL, LDO_LVL, C1-, C2- Voltage to AGND
PGND Voltage to AGND
-0.3 to 6.0
-0.3 to VOUT + 0.3
-0.3 to VIN + 0.3
-0.3 to 0.3
V
V
V
V
TJ
TLEAD
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
-40 to 150
°C
°C
300
Thermal Information3, 4
Symbol Description
Value
Units
PD
ΘJA
Maximum Power Dissipation
Maximum Thermal Resistance
2.0
50
W
°C/W
1. Backlight and Flash Configuration within a part number is configured though the I2C serial interface. For example, clearing the MEQS flag (set to “0”) in the AAT2860-1’s REG2
register will configure BL1-BL4 LED outputs as MAIN and BL5-BL7 outputs as SUB.
2. 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.
3. Derate 20 mW/°C above 25°C ambient temperature.
4. Mounted on a FR4 circuit board.
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2860.2008.05.1.0
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PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Electrical Characteristics1
VIN = 3.6V; CIN = 4.7µF; COUT = CLDO(A, B, C) = 2.2μF; C1 = C2 = 1µF; TA = -40°C to +85°C, unless otherwise noted.
Typical values are TA = 25°C.
Symbol Description
VIN IN Operating Voltage Range
Conditions
Min Typ Max Units
2.7
5.5
V
LED_SEL = IN, LDO_SEL = FL_LVL =
AGND; ADDR = 02H, DATA = 4CH
0.65
mA
2X Mode; LED_SEL = IN, FL_LVL = LDO_
SEL = AGND; BL1-BL7 = OPEN
2X Mode; LED_SEL = IN, FL_LVL = IN;
LDO_SEL = AGND; FL1-FL2 = OPEN
LED_SEL = FL_LVL = AGND, LDO_SEL =
IN; ADDR = 01H; DATA = 0EH; No Load
LED_SEL, LDO_SEL, FL_LVL = AGND
5.5
5.5
mA
mA
µA
IIN
IN Operating Current
220
1.0
IIN(SHDN)
TSD
TSD(HYS)
IN Shutdown Current
Over-Temperature Shutdown Threshold
Over-Temperature Shutdown Hysteresis
µA
˚C
˚C
140
15
Charge Pump Section
BL1-BL7 Charge Pump Mode Transition
Hysteresis
FL1-FL2 Charge Pump Mode Transition
Hysteresis
LED_SEL = IN, ADDR = 02H, DATA = 6CH;
FL_LVL = AGND, LDO_SEL = AGND
VIN(TH_H, BL)
VIN(TH_H, FL)
0.15
1
V
V
fOSC
tCP(SS)
Charge Pump Oscillator Frequency
Charge Pump Soft-start Time
TA = 25°C
TA = 25°C
1
100
MHz
µs
BL1-BL5, BL6/FL1, BL7/FL2 LED Drivers
tLED(SU)
LED Output Current Start-up Time
OUT: 0V to IN
20
30
µs
LED_SEL = IN, ADDR=02H, DATA=6CH;
VIN – VF = 1V; FL_LVL = LDO_SEL = AGND
IBLx
BL1-BL7 Current Accuracy
27
33
mA
IBL_(DAT-
A7DH)
LED_SEL = IN, ADDR=02H, DATA=7DH;
VIN – VF = 1V; FL_LVL = LDO_SEL = AGND
LED_SEL = IN, ADDR=02H, DATA=6CH;
VIN – VF = 1V; FL_LVL = LDO_SEL = AGND
LED_SEL = IN, ADDR=02H, DATA=60H,
VIN – VF = 1V; FL_LVL = LDO_SEL = AGND
LED_SEL = IN, ADDR=02H, DATA=6CH;
VIN – VF = 1V; FL_LVL = LDO_SEL = AGND
BL1-BL7 Current Accuracy
2.55
3
3
3.45
mA
%
V
ΔI(BLx)
/
BL1-BL7 Current Matching2
IBL(AVG)
VBL_(TH)
BL1-BL7 Charge Pump Transition Threshold
BL1-BL7 Automatic Fade Out Timer
0.18
1
tFADE
s
LED_SEL = FL_LVL = IN, ADDR=04H,
DATA=03H; VIN - VF = 1V, LDO_SEL =
AGND
LED_SEL = FL_LVL = IN, ADDR = 04H,
DATA=60H; VIN - VF = 1V, LDO_SEL =
AGND
LED_SEL = FL_LVL = IN, ADDR = 04H,
DATA=03H; VIN - VF = 1V, LDO_SEL=
AGND
LED_SEL = FL_LVL = IN, ADDR = 04H,
DATA=60H; VIN - VF = 1V, LDO_SEL =
AGND
IFL[1/2]
FL1, FL2 Current Accuracy, -4 Option
FL1, FL2 Current Accuracy, -4 Option
FL2 Current Accuracy, -2 and -3 Options
FL2 Current Accuracy, -2 and -3 Options
270
54
300
60
330
66
mA
mA
mA
mA
IFL[1/2]
540
108
600
120
660
132
IFL2
IFL2
1. The AAT2860 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correla-
tion with statistical process controls.
2. Current matching is defined as the deviation of any sink/channel current from the average of all active channels.
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2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Electrical Characteristics1
VIN = 3.6V; CIN = 4.7µF; COUT = CLDO(A, B, C) = 2.2μF; C1 = C2 = 1µF; TA = -40°C to +85°C, unless otherwise noted.
Typical values are TA = 25°C.
Symbol
Description
Conditions
Min Typ Max Units
LDO Regulators
ILDO = 1mA to 300mA; TA = 25°C
-1.5
-3
+1.5
+3
%
%
ΔVLDO[A/B/C]
VLDO[A/B/C]
/
LDOA, LDOB, LDOC Output
Voltage Tolerance
I
LDO = 1mA to 300mA; TA = -40°C to +85°C
LDOA, LDOB, LDOC Maximum
Load Current
LDOA, LDOB, LDOC Dropout
Voltage2
ILDO[A/B/C](MAX)
300
mA
mV
%/V
dB
VLDO[A/B/C](DO)
∆VLDO
VLDO[A/B/C] ≥ 2.7V; ILDO = 150mA
VIN = (VLDO[A/B/C] + 1V) to 5V
ILDO[A/B/C] =10mA, 1kHz
75
0.09
40
150
/
Line Regulation
VLDO*∆VIN
LDOA, LDOB, LDOC Power
Supply Rejection Ratio
PSRR[A/B/C]
LDOA, LDOB, LDOC Auto-
Discharge Resistance
RLDO_(DCHG)
20
Ω
I2C Logic and Control Interface
SDA, SCL, LED_SEL, FL_LVL,
LDO_SEL Input Low Threshold
SDA, SCL, LED_SEL, FL_LVL,
LDO_SEL Input High Threshold
SDA, SCL, LED_SEL, FL_LVL,
VIL
VIH
IIN
2.7V ≤ VIN ≤ 5.5V
0.4
V
V
2.7V ≤ VIN ≤ 5.5V
1.4
-1
SDA = SCL = LED_SEL = FL_LVL = LDO_SEL = 5V
1
µA
LDO_SEL Input Leakage Current
fSCL
tLOW
tHIGH
tHD_STA
tSU_STA
tSU_DAT
tHD_DAT
tSU_STO
SCL Clock Frequency
SCL Clock Low Period
SCL Clock High Period
Hold Time START Condition
Setup Time for Repeat START
SDA Data Setup Time
SDA Data HOLD Time
Setup Time for STOP Condition
0
400
kHz
µs
µs
µs
µs
ns
µs
µs
1.3
0.6
0.6
0.6
500
0.5
0.6
Bus Free Time Between STOP
and START Conditions
tBUF
1.3
µs
1. The AAT2860 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correla-
tion with statistical process controls.
2. VDO[A/B/C] is defined as VIN – LDO[A/B/C] when LDO[A/B/C] is 98% of nominal.
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2860.2008.05.1.0
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PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
I2C Compatible Interface Timing Details
t
t
t
t
t
t
t
t
t
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2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Typical Characteristics
Backlight Mode Efficiency vs. Input Voltage
Flash Efficiency vs. Input Voltage
100
90
100
90
80
70
60
50
40
30
160mA/ch, VF = 3.15V
320mA/ch, VF = 3.25V
80
70
60
50
30mA/ch, VF = 3.95V
40
15mA/ch, VF = 3.5V
4.2mA/ch, VF = 3.4V
30
2.7
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
Input Voltage (V)
Backlight Current Matching vs. Temperature
Charge Pump Output Turn-On Characteristic
(VIN = 3.6V; 30mA/Channel)
(VIN = 3.6V; 0mA/Channel; COUT = 2.2V)
33
32
31
30
29
4
2
0
4
3
2
1
0
Channel 1 - Channel 5/6/7
28
27
26
25
-40
-15
10
35
60
85
Temperature (°C)
Time (20µs/div)
Flash Mode Turn-On Characteristic
Flash Mode Turn-On Characteristic
(VIN = 4.2V; 300mA/Channel; 1x Mode)
(VIN = 3.6V; 300mA/Channel; 1.5x Mode)
4
2
4
2
0
VFL_LVL
VFL_LVL
(2V/div)
(2V/div)
0
VOUT
(2V/div)
VFLX
(2V/div)
VOUT
(2V/div)
VFLX
(2V/div)
4
4
2
0
2
0
600
400
200
0
600
400
200
0
IIN
IIN
(200mA/div)
(200mA/div)
Time (20µs/div)
Time (50µs/div)
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2860.2008.05.1.0
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PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Typical Characteristics
Flash Mode Turn-On Characteristic
Backlight Mode Turn-On Characteristic
(VIN = 2.8V; 300mA/Channel; 2x Mode)
(VIN = 4.6V; 30mA/Channel; 1x Mode)
4
4
2
VFL_LVL
(2V/div)
VSDA
2
0
(2V/div)
0
VOUT
(2V/div)
VBLX
(2V/div)
VOUT
4
2
0
4
2
0
(2V/div)
VFLX
(2V/div)
600
400
200
0
200
100
0
IIN
IIN
(200mA/div)
(100mA/div)
Time (50µs/div)
Time (100µs/div)
Backlight Mode Turn-On Characteristic
Backlight Mode Turn-On Characteristic
(VIN = 3.6V; 30mA/Channel; 1.5x Mode)
(VIN = 3.2V; 30mA/Channel; 2x Mode)
4
4
VSDA
VSDA
2
0
2
0
(2V/div)
(2V/div)
VOUT
(2V/div)
VBLX
(2V/div)
VOUT
(2V/div)
VBLX
(2V/div)
4
2
0
4
2
0
400
200
0
400
200
0
IIN
IIN
(200mA/div)
(200mA/div)
Time (100µs/div)
Time (100µs/div)
Backlight Mode Turn-Off Characteristic
Operating Characteristic
(VIN = 3.6V; 30mA/Channel; 1.5x Mode)
(30mA/Channel Backlight; 1.5x Mode; VIN = 3.6V; COUT = 2.2µF)
4
VSDA
20
10
0
2
0
(2V/div)
VDIODE
(2V/div)
4
2
0
100
50
0
2
0
-50
IIN
(2mA/div)
Time (500ns/div)
Time (200µs/div)
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2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Typical Characteristics
Operating Characteristic
LDOs A/B/C Load Regulation
(30mA/Channel Backlight; 2x Mode; VIN = 3.2V; COUT = 2.2µF)
(VIN = 3.6V)
1.5
1.0
VLDO = 3.0V
VLDO = 1.5V
20
10
0
0.5
20
10
0
0.0
-0.5
-1.0
-1.5
-10
-20
0.1
1
10
100
1000
Load Current (mA)
Time (500ns/div)
LDO Output Voltage vs Temperature
LDOs A/B/C Line Regulation
(VIN = 3.6V; ILDO = 0mA)
(ILDO = 10mA)
1.5
1.0
1.5
VLDO = 3.0V
VLDO = 1.5V
VLDO = 3.0V
VLDO = 1.5V
1
0.5
0
0.5
0.0
-0.5
-1
-0.5
-1.0
-1.5
-1.5
-40
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
-15
10
35
60
85
Temperature (°C)
Input Voltage (V)
LDOs A/B/C Load Transient Response
LDOs A/B/C Line Transient Response
(ILDO = 10mA to 200mA; VIN = 3.6V; VLDO = 1.8V; CLDO = 2.2µF)
(VIN = 3.6V to 4.2V; ILDO = 10mA; VLDO = 1.8V; CLDO = 2.2µF)
200
100
0
4.4
4.0
3.6
2.00
1.90
1.80
1.70
1.60
1.82
1.81
1.80
1.79
1.78
Time (20µs/div)
Time (1ms/div)
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2860.2008.05.1.0
9
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Typical Characteristics
LDOs A/B/C Turn-On Characteristic
LDOs A/B/C Turn-On Characteristic
(VLDO = 3.0V; VIN = 3.6V; CLDO = 2.2µF)
(VLDO = 1.5V; VIN = 3.6V; CLDO = 2.2µF)
4
2
0
4
2
0
4
3
2
1
0
1.5
1.0
0.5
0.0
Time (20µs/div)
Time (20µs/div)
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10
2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Functional Block Diagram
IN IN
C1-
LDOA
LDOB
1x/1.5x/2x
Tri-mode
Charge pump
C1+
C2-
C2+
OUT
LDOC
REF
7
BL1
SDA
SCL
BL2
BL3
BL4
Control
Logic
LED_SEL
FL_LVL
BL5
BL6/FL1
BL7/FL2
LDO_SEL
AAT2860-x
PGND
AGND
or the flash current sink/channel drops below 450mV,
the charge pump goes to the next higher mode (from 1x
to 1.5x or from 1.5x to 2x mode) to maintain sufficient
LED voltage for constant LED current. The AAT2860-x
continuously monitors the LED forward voltages and
uses the input voltage to determine when to reduce the
charge pump mode for better efficiency. There is also a
150mV mode-transition hysteresis that prevents the
charge pump from oscillating between modes.
Functional Description
The AAT2860-x is a highly integrated backlight and
photo-flash driver with three LDO regulators. The charge
pump LED driver powers the backlight and flash LEDs
from the 2.7V to 5.5V input voltage. The LDO regulators
get their power from the same input and produce regu-
lated output voltage between 1.5V and 3.0V. Control of
the LEDs and the LDO output voltage is through an I2C
compatible serial interface for easy programming.
LED Current Control
LED Drivers
Both the backlight and flash LED currents are controlled
through an I2C compatible serial interface. The backlight
LED current can be set between 0.5mA and 31mA in
1mA steps while the flash LED current can be set
between 0mA and 300mA in 20mA steps. The backlight
LED currents match to within 3% while the flash LED
currents match to within 5%.
The AAT2860-x drives up to seven backlight LEDs up to
31mA each and up to two flash LEDs up to 300mA each.
The LEDs are driven from a charge pump to insure that
constant current is maintained over the entire battery
voltage range. The charge pump automatically switches
from 1x, 1.5x, and 2x modes and back to maintain the
LED current while minimizing power loss for high effi-
ciency. The charge pump operates at the high 1MHz
switching frequency allowing the use of small 1μF ceram-
ic fly capacitors.
To eliminate the latency of the I2C compatible serial
interface, the flash LED is enabled through a dedicated
input, FL_LVL. The AAT2860-x also include a safety
timer that prevents overstress of the flash LED(s). This
is important because many flash LEDs operate for a brief
period beyond their steady-state operating limitations. If
the flash driving hardware and/or software fails to turn
The charge pump is controlled by the voltage across the
LED current sinks. When any one of the active backlight
current sink sink/channel voltages drops below 180mV
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2860.2008.05.1.0
11
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
the LED off, the safety timer insures that the LED or
other circuitry is not damaged.
always be set to “0”. The timing diagram in Figure 1 below
shows the typical transmission protocol.
Both the backlight and flash LED currents are programmed
through the I2C compatible serial interface as are the
backlight fade timer, the flash safety timer, and the torch/
flash inhibit current levels. See the “I2C Compatible Serial
Interface” section of this datasheet for more information
on setting the LED currents. To enable the flash LED(s),
strobe both LED_SEL and FL_LVL inputs low-to-high. As
long as FL_LVL signal is held high, the flash LED remains
on unless it is on longer than the safety timer period. If
this occurs, the flash LED is turned off.
I2C Compatible Serial Interface Protocol
The I2C compatible serial interface protocol is shown in
Figure 1. Devices on the bus can be either master or
target devices. Both master and target devices can both
send and receive data over the bus, with the difference
being that the master device controls all communication
on the bus. The AAT2860-x acts as a target device on the
bus and is only capable of receiving data and does not
transmit data over the bus.
The I2C communications begin with the master generat-
ing a START condition. Next, the master transmits the
7-bit device address and a read/write bit. Each target
device on the bus has a unique address. If the address
transmitted by the master matches the device address,
the target device transmits an acknowledge (ACK) signal
to indicate that it is ready to receive data. Since the
AAT2860-x only reads from the master, the read/write
bit must be set to “0”. Next, the master transmits an
8-bit register address, and the target device transmits
an ACK to indicate that it has received the register
address. Next, the master transmits an 8-bit data word,
and again the target device transmits an ACK indicating
that it has received the data. This process continues until
the master is finished writing to the target device at
which time the master generates a STOP condition.
LDO Regulators
The AAT2860-x family include three LDO regulators. These
regulators are powered from the battery and produce a
fixed output voltage set through the I2C compatible serial
interface. The output voltage can be set to one of 16 out-
put voltages between 1.5V and 3.0V. The LDOs can also be
turned on/off through the I2C compatible serial interface.
The LDO regulators require only a small 2.2μF ceramic
output capacitor for stability. If improved load transient
response is required, larger-valued capacitors can be
used without stability degradation.
I2C Compatible Serial Interface
The AAT2860-x uses an I2C serial interface to set the LED
currents, the flash timer period, the LDO on/off and out-
put voltage, as well as other housekeeping functions. The
I2C interface takes input from a master device while the
AAT2860-x acts as a target to the master. The I2C protocol
uses two open-drain inputs; SDA (serial data line) and
SCL (serial clock line). Both inputs require an external pull
up resistor, typically to the input voltage. The I2C protocol
is bidirectional and allows target devices and masters to
both read and write to the bus. AAT2860 only supports
the write protocol and therefore the Read/Write bit must
START and STOP Conditions
START and STOP conditions are always generated by the
master. Prior to initiating a START, both the SDA and SCL
pin are active. As shown in Figure 2, a START condition is
when the master pulls the SDA line low and, after the
START condition hold time (tHD_STA), the master strobes the
SCL line low. A START condition acts as a signal to devices
on the bus that the device producing the START condition
is active and will be communicating on the bus.
SCL
SDA
Start
AAT 2860 Device
Address 0x60
W
ACK
Address = 02h
ACK
Data = 40h
ACK Stop
Figure 1: Typical I2C Timing Diagram.
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12
2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
A STOP condition, as shown in Figure 2, is when SCL
changes from low to high followed after the STOP condi-
tion setup time (tSU_STO), by the SDA low-to-high transi-
tion. The master does not issue an ACK and releases
both the SCL and SDA line.
signifies the power on reset (POR) value of a register, the
superscript "2" signifies the default value of "1" for a par-
ticular bit of a register, and the superscript "3" signifies
"Don't Care" or "Reserved."
LDO Control Registers, REG0 and REG1
Transferring Data
Configuring and controlling the AAT2860-x’s three LDO
regulators is performed by applying a low-to-high strobe
on the LDO_SEL pin and then programming registers
REG0 and REG1 over the I2C compatible interface. Two
4-bit nibbles in REG0 set the output voltages for LDOA
and LDOB to one of 16 levels. In REG1, the most-signif-
icant nibble programs LDOC’s output voltage while the
least-significant 4-bit nibble controls each LDO’s ON/OFF
status. Upon power-on reset (POR), all three LDO out-
puts are held to 0V or AGND. The programmed LDO
output voltage will only appear after writing a “1” to
each or all REG1[D3:D1] locations. If a high-to-low tran-
sition is applied to the LDO_SEL pin, all three LDO out-
puts are forced to 0V and the register contents are reset
to their POR values. The available LDO output voltages
are shown in Table 2.
Addresses and data are sent with the most significant bit
transmitted first and the least significant bit transmitted
last. After each address or data transmission, the target
device transmits an ACK signal to indicate that it has
received the transmission. The ACK signal is generated
by the target after the master releases the SDA data line
by driving the SDA data line low.
I2C Serial Programming Registers
The AAT2860’s I2C programming registers are listed in
Table 1. There are six registers, two for backlight LED
configuration/control, one for flash/lamp LED configura-
tion/control, and two registers to control the three LDOs.
For the remainder of this document the superscript "1"
D7
LDOA[3]
LDOC[3]
X3
D6
D5
D4
LODA[0]
LODC[0]
WM[4]
WS[4]
F_HI[0]
X3
D3
LDOB[3]
ENLDO_C
WM[3]
WS[3]
D2
LDOB[2]
ENLDO_B
WM[2]
WS[2]
D1
D0
LODB[0]
X3
LDOA[2]
LDOC[2]
MEQS2
LDOA[1]
LDOC[1]
MAIN_ON
SUB_ON
F_HI[1]
X3
LDOB[1]
ENLDO_A
WM[1]
REG0
REG1
REG2
REG3
REG4
REG5
WM[0]
FLOOR[1]
F_HI[3]2
X3
FLOOR[0]
F_HI[2]2
X3
WS[1]
WS[0]
F_TIME[1]
X3
F_TIME[0]
X3
F_LO[1]2
NOFADE_M2
F_LO[0]2
NOFADE_S2
Table 1: AAT2860-x Configuration/Control Register Allocation.
LDOx[4:0]
LDO VOUT [A/B/C] (V)
LDOx[4:0]
LDO VOUT [A/B/C] (V)
00001
0001
0010
0011
0100
0101
0110
0111
1.51
1.6
1.7
1.8
1.9
2.0
2.1
2.2
1000
1001
1010
1011
1100
1101
1110
1111
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
Table 2: LDO[A:C] Output Voltage Control Data
1. Denotes the default (power-on-reset) value.
2. Denotes default value is "1" or ON.
3. Don't Care or Reserved.
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2860.2008.05.1.0
13
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
t
t
2
Figure 2: I C STOP and START Conditions.
START: A High “1” to Low “0” Transition on the SDA Line While SCL is High “1”
STOP: A Low “0” to High “1” Transition on the SDA Line While SCL is High “1”
2
Figure 3: I C Address Bit;
7-bit Slave Address (A6-A0), 1-bit Read/Write (R/W), 1-bit Acknowledge (ACK).
2
Figure 4: I C Register Address and Data Bit Map;
8-bit Data (D7-D0), 1-bit Acknowledge (ACK).
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14
2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Based on the programmed LED current level set by
BL1-BL7 Backlight Control Registers,
REG2, REG3, and REG5
WM[4:0](REG2[D4:D0])and/orWS[4:0](REG3[D4:D0]),
the AAT2860-x increases/decreases linearly from/to the
programmed FLOOR (REG3[D7:D6]) level to/from the
current level set for the MAIN (REG2[D4:D0]) and SUB
(REG3[D4:D0]) groups during LED ON/OFF transitions.
The AAT2860-x’s internal fade response time is approxi-
mately 1 second. In addition, the AAT2860-x provides
four settings selectable over the I2C interface for the fade
function’s LED current floor and these settings are illus-
trated in Table 5.
The AAT2860-x’s I2C registers REG2 and REG3 control
the backlight LED configuration and output current level
in each group of outputs. REG2[D6] (MEQS) defines
whether all seven LED outputs are controlled as a single
group (MEQS = 1 = POR default setting) or are divided
into two sets (by writing a “0” into REG2[D6]) for MAIN/
SUB display applications according to the "Part Number
Descriptions" table.
The default condition for all backlight outputs (BL1-BL5/
BL6/BL7) is OFF after power-up. If the BL1-BL5/BL6/BL7
outputs are grouped together, REG2 Data Bit 5 (MAIN_
ON) is the ON/OFF control for the group; in this case,
REG3[D5] (SUB_ON register bit) is ignored. In the case
of the AAT2860-1, setting MEQS = 0 after POR groups
the BL1-BL4 outputs together as MAIN and groups the
BL5-BL7 outputs as SUB. In this case, REG2[D5] is the
ON/OFF control for the MAIN group and REG3[D5] is the
ON/OFF control for the SUB group.
FL1-FL2 Flash Driver Control Register REG4
Metal-mask options of the base AAT2860-x design have
been configured for backlight and flash/torch applications.
As shown in the "Part Number Descriptions" table, there
are three combinations for backlight and flash available in
this family: the AAT2860-2 (6M+0S+1FL or 4M+2S+1FL),
the AAT2860-3 (6M+0S+1FL or 5M+1S+1FL), or the
AAT2860-4 (5M+0S+2FL or 4M+1S+2FL). The configura-
tion of the LED outputs is controlled by the MEQS bit. In
all cases, the MEQS POR default value of “1” or a user-
programmed value of “0” selects the configuration of the
AAT2860-2/3/4 according to Table 6.
The AAT2860-x LMU also provides an internal LED current
fade function. Fade functionality simply allows for the
turning on/off of the LEDs in a smooth controlled transi-
tion. The AAT2860 does not have to be manually pro-
grammed to avoid the abrupt changes in lighting when
white LED drivers are tuned-on and/or turned-off. The
fade-in/fade-out operation occurs only during LED on/off
transitions. The fade response time is constant regardless
of the LED current level. This feature is useful in those
applications where turning ON/OFF the backlight current
using a smooth transition versus an abrupt ON-to-OFF
transition is preferred. If MEQS = 1(REG2[D6]), then fade
will be disabled in all LED’s when NO_FADE_M(REG5[D1])
is written to 1. In this case, the contents of NO_
FADE_S(REG5[D0]) are ignored. If MEQS = 0, then fade
can be disabled independently for the MAIN and SUB LED
groups using the bits NO_FADE_M and NO_FADE_S.
In all options, the BLX current outputs can be programmed
as a single unit (MEQS = 1) or configured in a MAIN/SUB
arrangement with separate current levels between MAIN
and SUB (MEQS = 0). In the case of the AAT2860-2/3
options where the MEQS bit has been programmed as a
“0,” the BL7 LED output is internally re-configured as a
single flash/lamp current output, FL. In these options, the
maximum available current from the flash output is 600mA
(see Table 7) and maximum available current for torch or
flash inhibit is 120mA (see Table 9). For the AAT2860-4,
the BL6 and the BL7 outputs are internally reconfigured as
flash current outputs, FL1 and FL2, respectively, where
each flash output is capable of supplying up to 300mA in
full-flash mode and up to 60mA in torch mode.
w w w . a n a l o g i c t e c h . c o m
2860.2008.05.1.0
15
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
D7
D6
MEQS2
FLOOR[0]
X3
D5
MAIN_ON
SUB_ON
X3
D4
WM[4]
WS[4]
X3
D3
WM[3]
WS[3]
X3
D2
WM[2]
WS[2]
X3
D1
WM[1]
D0
WM[0]
X3
FLOOR[1]
X3
REG2
REG3
REG5
WS[1]
WS[0]
NOFADE_M2
NOFADE_S2
Table 3: AAT2860 BL1-BLX Backlight Control Register Allocation.
WM[4:0], WS[4:0]
LED Current (mA)
WM[4:0], WS[4:0]
LED Current (mA)
000001
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
311
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
10000
10001
10010
10011
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0.5
Table 4: MAIN/SUB LED Current - WM/WS[4:0].
For each one of the three options in Table 6, setting/pro-
gramming the bits in REG4 (see Table 7) sets the full-
scale flash current, the torch current levels, and flash
safety time duration. The most-significant 4-bit nibble
(REG1[D7:D4], or F_HI[3:0]) of the 8-bit data word sets
the full-scale flash LED current, the middle two bits
(REG4[D3:D2], or F_TIME[1:0]) set the flash safety dura-
tion, and the last two bits (REG4[D1:D0], or F_LO[1:0])
are used to set the torch current level.
FLOOR[1:0]
Fade In/Out Current Level (mA)
001
01
10
11
0.48
0.97
1.94
2.90
Table 5: Main/Sub LED Current
Fade In/Out Level Control.
MEQS Bit (REG2 Data Bit[6])
Part
Number
“1” (Default)
“0”
AAT2860-2
AAT2860-3
AAT2860-4
6M+0S+1FL
6M+0S+1FL
5M+0S+2FL
4M+2S+1FL
5M+1S+1FL
4M+1S+2FL
Table 6: AAT2860-2/3/4 Flash Driver
Control Register Allocation.
1. Denotes default (power-on-reset) value.
2. Denotes default value is "1" or ON.
3. Don't Care or Reserved.
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16
2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
D7
D6
D5
D4
D3
D2
D1
D0
F_HI[3]2
F_HI[2]2
F_HI[1]
F_HI[0]
F_TIME[1]
F_TIME[0]
F_LO[1]2
F_LO[0]2
REG4
Table 7: AAT2860-x Flash/Torch Control Register Allocation.
Applications Information
Flash Current (mA) per Output
F_HI[3:0]
AAT2860-2 or -3
AAT2860-4
LED Selection
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
11001
1101
1110
1111
600
560
520
480
440
400
360
320
280
240
200
160
1201
80
300
280
260
240
220
200
180
160
140
120
100
80
The AAT2860-x is specifically intended for driving white
LEDs. However, the device design will allow the AAT2860-x
to drive most types of LEDs with forward voltage specifi-
cations ranging from 2.0V to 4.7V. LED applications may
include mixed arrangements for display backlighting,
color (RGB) LEDs, infrared (IR) diodes and any other load
needing a constant current source generated from a vary-
ing input voltage. Since the BL1 to BL5/BL6(FL1)/
BL7(FL2) constant current sinks/channels are matched
with negligible voltage dependence, the constant current
channels will be matched regardless of the specific LED
forward voltage (VF) levels.
601
40
20
40
OFF
The current sinks/channels in the AAT2860-x 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.
OFF
Table 8: Flash LED Current Register, F_HI[3:0].
F_TIME[1:0]
Flash Time (sec)
001
01
10
11
21
1
Device Switching Noise Performance
The AAT2860-x operates at a frequency of approximate-
ly 1MHz to control noise and limit harmonics that can
interfere with the RF operation of cellular telephone
handsetsorothercommunicationdevices. TheAAT2860-x
soft-start feature prevents noise transient effects associ-
ated with in-rush currents during the start up of the
charge pump circuit.
0.5
Always ON
Table 9: Flash Safety Timer Data, F_TIME[1:0].
Total Output Torch Current (mA)
F_LO[1:0]
AAT2860-2 or -3
AAT2860-4
00
01
10
111
120
80
40
01
60
40
20
01
Power Efficiency and Device Evaluation
Charge-pump efficiency discussion in the following sec-
tions accounts only for the efficiency of the charge pump
section itself. Due to the unique circuit architecture and
design of the AAT2860-x, it is very difficult to measure
efficiency in terms of a percent value comparing input
power over output power.
Table 10: Torch Data, F_LO[1:0].
1. Denotes the default (power-on-reset) value.
2. Denotes default value is "1" or ON.
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2860.2008.05.1.0
17
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Since the AAT2860-x outputs are pure constant current
sinks and typically drive individual loads, it is difficult to
measure the output voltage for a given output (BL1 to
BL5, BL6/FL1, and BL7/FL2) 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.
The expression to define the estimated ideal efficiency
(η) for the AAT2860 in 1x mode is as follows:
PLEDs VLED1 · ILED1 + ... + VLEDX · ILEDX
η =
=
PIN
VIN · IIN
X · VLEDX · I
VIN · IIN
η =
η =
LEDX ; X = 1, 2, 3, ..., 6 or 7 and IIN = X · ILEDX
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 “% efficiency”.
VLEDX
VIN
The AAT2860’s charge pump is a fractional charge pump
which will boost the input supply voltage in the event
where VIN is less then the required output voltage across
the backlight white LED load. The efficiency can be simply
defined as a linear voltage regulator with an effective
backlight white LED forward voltage that is equal to one
and a half (1.5x mode) times the input voltage.
The AAT2860-x efficiency may be quantified under very
specific conditions and is dependent upon the input volt-
age versus the output voltage seen across the loads
applied to outputs BL1 through BL5, BL6(FL1), and
BL7(FL2) for a given constant current setting. Depending
on the combination of VIN and voltages sensed at the
current sinks/channels, the device will operate in “Load
Switch” mode. When any one of the voltages sensed at
the current sinks/channels nears dropout the device will
operate in 1.5x or 2x charge pump mode. Each of these
modes will yield different efficiency values. One should
refer to the following two sections for explanations for
each operational mode.
With an ideal 1.5x charge pump, the input current is
1.5x of the output current. The expression to define the
estimated ideal efficiency (η) for the AAT2860 in 1.5x
mode is as follows:
PLEDs VLED1 · ILED1 + ... + VLEDX · ILEDX
η =
η =
η =
=
PIN
VIN · IIN
X · VLEDX · I
VIN · IIN
LEDX ; X = 1, 2, 3, ..., 6 or 7 and IIN = 1.5(X · ILEDX
)
VLEDX
1.5VIN
Device Power Efficiency
The same calculations apply for the AAT2860 in 2x mode
where for an ideal 2x charge pump, the input current is
2x of the output current. The expression for the esti-
mated ideal efficiency (η) for the AAT2860 in 2x mode is
as follows:
The AAT2860’s charge pump conversion efficiency is
defined as the power delivered to the white LED load
divided by the input power:
PLEDs VLED1 · ILED1 + ... + VLEDX · ILEDX
η =
=
PIN
VIN · IIN
PLEDs VLED1 · ILED1 + VLED2 · ILED2
η =
=
PIN
VIN · IIN
VLEDx = White LED Forward Voltage (VF)
ILEDx = White LED Bias Current (ID)
X = Number of White LEDs
X · VLEDX · I
VIN · IIN
η =
η =
LEDX ; X = 1, 2, 3,..., 6 or 7 and IIN = 2(X · ILEDX
)
VLEDX
2VIN
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18
2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Capacitor Selection
PCB Layout
Careful selection of the eight external capacitors CIN, C1,
C2, CLDO(A/B/C), and COUT are important because they will
affect turn on time, output ripple and transient perfor-
mance. Optimum performance will be obtained when low
ESR (<100mΩ) ceramic capacitors are used. In general,
low ESR is defined as a resistance that is less than
100mΩ.
To achieve adequate electrical and thermal performance,
careful attention must be given to the PCB layout. In the
worst-case operating condition, the chip must dissipate
considerable power at full load. Adequate heat-sinking
must be achieved to ensure intended operation.
Figures 6 and 7 illustrate an example PCB layout. The
bottom of the package features an exposed metal pad.
The exposed pad acts, thermally, to transfer heat from
the chip and, electrically, as a ground connection.
X7R and X5R type ceramic capacitors are highly recom-
mended over all other types of capacitors for use with
the AAT2860. For the charge pump section, a 1µF or
greater capacitor is required for the fly (C1 and C2)
capacitors. The three LDOs require a 2.2µF or greater
output capacitor. The required input capacitor (CIN) is
The junction-to-ambient thermal resistance (θJA) for the
connection can be significantly reduced by following a
couple of important PCB design guidelines. The PCB area
directly underneath the package should be plated so that
the exposed paddle can be mated to the top layer PCB
copper during the reflow process. Multiple copper plated
thru-holes should be used to electrically and thermally
connect the top surface pad area to additional ground
plane(s).
4.7μF or greater and the required output capacitor (COUT
)
is 2.2μF or greater.
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 printed circuit board (PCB) footprint,
and is non-polarized. Low ESR ceramic capacitors maxi-
mize charge pump transient response.
The chip ground is internally connected to both the
exposed pad and to the AGND and PGND pins. It is good
practice to connect the GND pins to the exposed pad
area with traces.
Before choosing a particular capacitor, verify the capaci-
tor’s performance with the characteristics illustrated in
the component’s data sheet. Performance verification
will help avoid undesirable component related perfor-
mance deficiencies. Suggested typical ceramic capacitor
components for the AAT2860 are listed in Table 11.
The flying capacitors (C1 and C2), input capacitors (C3
and C4), and output capacitor (C5, C6, C7, and C8)
should be connected as close as possible to the IC. In
addition to the external passive components being
placed as close as possible to the IC, all traces connect-
ing the AAT2860 should be as short and wide as possible
to minimize path resistance and potential coupling.
Manufacturer
Part Number
Value
Voltage
Temp. Co.
Case
0603ZD105K
0603ZD225K
1μF
2.2μF
1μF
2.2μF
4.7μF
1μF
10
10
25
16
10
16
10
10
AVX
X5R
0603
C1608X5R1E105K
C1608X5R1C225K
C1608X5R1A475K
GRM188R61C105K
GRM188R61A225K
LMK107BJ475KA
TDK
X5R
0603
Murata
X5R
X5R
0603
0603
2.2μF
4.7μF
Taiyo Yuden
Table 11: Surface Mount Capacitors.
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2860.2008.05.1.0
19
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
OUT
DC+
R5
C4
IN
C1
D7
DF2
D6 DF1
U1
AAT2860-X
D5 D4 D3 D2 D1
DC+
R8
C8
C2
19
1
2
3
4
5
6
7
OUT
BL7/FL2
18
17
16
15
14
13
C2+
BL6/FL1
BL5
SDA
SCL
SDA
SCL
BL4
LED_SEL
FL_LVL
LDO_SEL
BL3
R7
FLASH
DC+
BL2
BL1
DC+
R4
C5
C6
C7
U2
AAT4296
C3
IN
DC+
DC+
R1
R2 R3
U3
PIC12F675
C9
R6
SW1
1
2
3
4
8
7
6
VDD
GP5
GP4
GP3
VSS
SCL
GP0
GP1
GP2
5
LED7
RED
SW2
SW3
SDA
Figure 5: AAT2860 Evaluation Board Schematic.
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20
2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Figure 6: AAT2860 Evaluation Board Top-Side View Layout.
Figure 7: AAT2860 Evaluation Board Bottom-Side View Layout.
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2860.2008.05.1.0
21
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
TQFN34-24
TQFN34-24
TQFN34-24
TQFN34-24
TQFN34-24
TQFN34-24
1GXYY
1WXYY
AAT2860IMK-1-T1
AAT2860IMK-2-T1
AAT2860IMK-3-T1
AAT2860IMK-4-T1
AAT2860IMK-5-T1
AAT2860IMK-6-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/about/quality.aspx.
Package Information
TQFN34-243
3.000 ± 0.050
1.700 ± 0.050
Index Area
(D/2 x E/2)
0.210 ± 0.040
R(5x)
0.400 BSC
Detail “A”
Detail “A”
Bottom View
Top View
Side View
+ 0.10
- 0.00
0
0.203 REF
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.
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22
2860.2008.05.1.0
PRODUCT DATASHEET
AAT2860
TM
ChargePump
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Advanced Analogic Technologies, Inc.
3230 Scott Boulevard, Santa Clara, CA 95054
Phone (408) 737-4600
Fax (408) 737-4611
© 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. Except as provided in AnalogicTech’s terms and
conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer’s applications, adequate
design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. Testing and other quality control 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 registered trademarks or trademarks of their respective holders.
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2860.2008.05.1.0
23
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