LTC3209EUF-2 [Linear]
600mA Main/Camera LED Controller; 600毫安主/相机LED控制器
| 型号： | LTC3209EUF-2 |
| 厂家： | 
Linear |
| 描述： | 600mA Main/Camera LED Controller |
| 文件： | 总20页 (文件大小：248K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC3209-1/LTC3209-2
600mA Main/Camera
LED Controller
U
FEATURES
DESCRIPTIO
The LTC®3209-1/LTC3209-2 are highly integrated
multidisplay LED controllers. These parts contain a high
efficiency, low noise charge pump to provide power to
MAIN, CAM and AUX LED displays. The LTC3209-1/
LTC3209-2 require only four small ceramic capacitors
andonecurrentsetresistortoformacompleteLEDpower
supply and current controller.
■
Multimode Charge Pump Provides Up to 94%
Efficiency (1x, 1.5x, 2x)
■
Up to 600mA Total Output Current
■
LTC3209-1: 8 Current Sources Available as
6 × 25mA MAIN, 1 × 400mA CAM and 1 × 15mA AUX
■
LTC3209-2: 8 Current Sources Available as
5 × 25mA MAIN, 2 × 200mA CAM and 1 × 15mA AUX
■
LED On/Off and Brightness Level Programmable
Themaximumdisplaycurrentsaresetbyasingleexternal
resistor. Current for each LED is controlled by a precision
internal current source. Dimming and On/Off for all dis-
playsisachievedviatheI2Cserialinterface. 256statesare
availablefortheMAINdisplay. Sixteenstatesareavailable
for the CAM display and four states are available for the
AUX display.
Using 2-Wire I2CTM Interface
■
Automatic Charge Pump Mode Switching or Fixed
Mode for Power Supply Generation
■
Low Noise Constant Frequency Operation*
■
Internal Soft-Start Limits Inrush Current During
Start-up and Mode Switching
■
Short Circuit/Thermal/Open-Shorted LED Protection
■
■
■
■
The charge pump optimizes efficiency based on the
voltage across the LED current sources. The part powers
upin1xmodeandwillautomaticallyswitchtoboostmode
whenever any enabled MAIN or CAM LED current source
begins to enter dropout. The first dropout switches the
part into 1.5x mode and a subsequent dropout switches
the part into 2x mode. The part resets to 1x mode
whenever a data bit is updated via the I2C port. The parts
are available in a 4mm × 4mm 20-lead QFN package.
256 Brightness States for MAIN Display
16 Brightness States for CAM Display
4 Brightness States for AUX Display
20-Lead (4mm ×U4mm) QFN Package
APPLICATIO S
■
Video/Camera Phones with QVGA+ Displays
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protected by U.S. Patents, including 6411531
U
TYPICAL APPLICATIO
LTC3209-1 6 MAIN/1 CAM Operation
LTC3209-2 5 MAIN/2 CAM Operation
2.2µF
2.2µF
2.2µF
2.2µF
MAIN
CAM
MAIN
CAM
C1P C1M C2P C2M
CPO
C1P C1M C2P C2M
CPO
V
BAT1,2
2.2µF
2.2µF
V
V
BAT
BAT
V
BAT1,2
RED
RED
2.2µF
2.2µF
LTC3209-2
LTC3209-1
SCL
SDA
SCL
SDA
2
2
6
5
2
I C
I C
MAIN1-6
CAM
MAIN1-5
CAM
LOW HI
CAMHL
AUX
GND
LOW HI
CAMHL
AUX
GND
3209 TA01
3209 TA02
R
R
REF
REF
24.3k
24.3k
320912fa
1
LTC3209-1/LTC3209-2
W W
U W
ABSOLUTE AXI U RATI GS
(Note 1)
VBAT, DVCC, CPO to GND ............................... –0.3 to 6V
SDA, SCL, CAMHL ..................... –0.3V to (DVCC + 0.3V)
ICAM1-2 (Note 5) .................................................. 250mA
CAM (Note 5) ...................................................... 500mA
CPO, RREF Short-Circuit Duration ....................Indefinite
Operating Temperature Range (Note 2) .. –40°C to 85°C
Storage Temperature Range ................. –65°C to 125°C
I
I
CPO (Note 4)....................................................... 700mA
IMAIN1-6 (Note 5)................................................... 31mA
IAUX (Note 5) ......................................................... 30mA
U
W
U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
TOP VIEW
20 19 18 17 16
20 19 18 17 16
CPO
MAIN1
MAIN2
MAIN3
MAIN4
1
2
3
4
5
15 SCL
CPO
MAIN1
MAIN2
MAIN3
MAIN4
1
2
3
4
5
15 SCL
14 SDA
14 SDA
21
8
13 CAMHL
12 CAM2
11 CAM1
21
8
13 CAMHL
12 CAM
11 DV
CC
6
7
9 10
6
7
9 10
UF PACKAGE
20-LEAD (4mm 4mm) PLASTIC QFN
UF PACKAGE
20-LEAD (4mm × 4mm) PLASTIC QFN
TJMAX = 125°C, θJA = 40°C/W
TJMAX = 125°C, θJA = 40°C/W
EXPOSED PAD IS GND (PIN 21), MUST BE SOLDERED TO PCB
EXPOSED PAD IS GND (PIN 21), MUST BE SOLDERED TO PCB
ORDER PART NUMBER
LTC3209EUF-1
UF PART MARKING
32091
ORDER PART NUMBER
LTC3209EUF-2
UF PART MARKING
32092
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
unless otherwise noted.
The
●
denotes the specifications which apply over the full operating
= 3.6V, DV = 3V, R = 24.3k, C1 = C2 = C3 = C4 = 2.2
temperature range, otherwise specifications are at T = 25
°
C. V
µF,
A
BAT1,2
CC
REF
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
Operating Voltage
Operating Current
●
2.9
4.5
V
BAT
I
I
I
I
= 0, 1x Mode, LED Disabled
= 0, 1.5x Mode
= 0, 2x Mode
0.4
2.7
4.5
mA
mA
mA
VBAT
CPO
CPO
CPO
V
UVLO Threshold
1.5
V
V
BAT
DV Operating Voltage
●
●
1.5
4.5
1
CC
DV Operating Current
DV = 1.8V, Serial Port Idle
µA
V
CC
CC
DV UVLO Threshold
1
3
CC
V
BAT
Shutdown Current
DV = 3V
CC
●
7
µA
320912fa
2
LTC3209-1/LTC3209-2
ELECTRICAL CHARACTERISTICS
unless otherwise noted.
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25
°
C. V
= 3.6V, DV = 3V, R = 24.3k, C1 = C2 = C3 = C4 = 2.2
REF
µF,
A
BAT1,2
CC
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
White LED Current (MAIN1-6), 8-Bit Linear DAC
Full-Scale LED Current
MAIN = 1V
MAIN = 1V
●
25
28
110
1
31
mA
µA
%
Minimum (1LSB) LED Current
LED Current Matching
Any Two MAIN Outputs at 50% FS
LED Dropout Voltage
Mode Switch Threshold, I
= FS
180
mV
MAINx
White LED Current (CAM), LTC3209-1, 4-Bit Linear DAC
Full-Scale LED Current
CAM = 1V
●
●
360
180
400
26.8
400
440
220
mA
mA
mV
Minimum (1LSB) LED Current
LED Dropout Voltage
CAM = 1V
Mode Switch Threshold, I
= FS
CAM
CAM
White LED Current (CAM1-2), LTC3209-2, 4-Bit Linear DAC
Full-Scale LED Current
CAM = 1V
200
13.3
1
mA
mA
%
Minimum (1LSB) LED Current
LED Current Matching
CAM = 1V
CAM1-2 at 50% FS
Mode Switch Threshold, I
LED Dropout Voltage
= FS
400
mV
AUX LED Current, 2-Bit Linear DAC
Full-Scale LED Current
AUX = 1V
AUX = 1V
●
12.5
13.75
4.4
15
mA
mA
mV
Minimum (1LSB) LED Current
V
I
= 1mA; C0, C1 = High
AUX
18
OL
Charge Pump (CPO)
1x Mode Output Impedance
1.5x Mode Output Impedance
2x Mode Output Impedance
CPO Voltage Regulation
0.5
2.7
3.2
Ω
Ω
Ω
V
V
V
V
= 3V, V
= 3V, V
= 4.2V (Note 3)
= 4.8V (Note 3)
= 2mA
BAT
BAT
CPO
CPO
CPO
1.5x Mode, I
2x Mode, I
4.6
5.1
= 2mA
CPO
CLOCK Frequency
0.85
MHz
SDA, SCL, CAMHL
V
V
V
(Low Level Input Voltage)
(High Level Input Voltage)
●
●
●
●
●
0.3 • DV
V
V
IL
CC
0.7 • DV
IH
OL
CC
, Digital Output Low (SDA)
I
= 3mA
0.16
0.4
1
V
PULLUP
I
I
SDA, SCL, CAMHL = DV
SDA, SCL, CAMHL = 0V
–1
–1
µA
µA
IH
IL
CC
1
Serial Port Timing (Notes 6, 7)
t
t
t
t
t
t
t
t
t
t
t
t
Clock Operating Frequency
400
kHz
µs
µs
µs
µs
ns
ns
ns
µs
µs
ns
ns
SCL
Bus Free Time Between Stop and Start Condition
Hold Time After (Repeated) Start Condition
Repeated Start Condition Setup Time
Stop Condition Setup Time
Data Hold Time
1.3
0.6
0.6
0.6
0
BUF
HD,STA
SU,STA
SU,STO
HD,DAT(OUT)
HD,DAT(IN)
SU,DAT
LOW
900
Input Data Hold Time
0
Data Setup Time
100
1.3
0.6
20
Clock Low Period
Clock High Period
HIGH
Clock Data Fall Time
300
300
f
Clock Data Rise Time
20
r
320912fa
3
LTC3209-1/LTC3209-2
ELECTRICAL CHARACTERISTICS
unless otherwise noted.
The
●
denotes the specifications which apply over the full operating
= 3.6V, DV = 3V, R = 24.3k, C1 = C2 = C3 = C4 = 2.2
temperature range, otherwise specifications are at T = 25
°
C. V
µF,
A
BAT1,2
CC
REF
PARAMETER
CONDITIONS
Spike Suppression Time
MIN
50
TYP
MAX
UNITS
t
ns
SP
R
REF
VR
RR
R
= 24.3k
●
1.20
20
1.23
1.26
30
V
REF
REF
Reference Resistor Range
kΩ
REF
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3209-1/LTC3209-2 are guaranteed to meet performance
specifications from 0°C to 70°C. Specifications over the –40°C to 85°C
ambient operating temperature range are assured by design,
Note 3: 1.5x mode output impedance is defined as (1.5V
– V )/I
.
.
BAT
CPO OUT
2x mode output impedance is defined as (2V
– V )/I
BAT
CPO OUT
Note 4: Based on long term current density limitations. Assumes an
operating duty cycle of ≤ 10% under absolute maximum conditions for
duration less than 10 seconds. Max Charge Pump current for continuous
operation is 300mA.
Note 5: Based on long term current density limitations.
characterization and correlation with statistical process controls.
Note 6: All values are referrenced to V and V levels.
IH
IL
Note 7: Guaranteed by design.
U W
TYPICAL PERFOR A CE CHARACTERISTICS T = 25°C unless otherwise noted
A
Mode Switch Fast Dropout Times
1.5x Mode CPO Ripple
2x Mode CPO Ripple
2x
1.5x
1x
V
V
CPO
CPO
V
CPO
20mV/DIV
20mV/DIV
1V/DIV
AC COUPLED
AC COUPLED
V
= 3.6V
= 200mA
= 2.2µF
V
= 3.6V
= 200mA
= 2.2µF
BAT
CPO
CPO
BAT
CPO
CPO
V
= 3.6V
BAT
REGC C2 = Hi
I
I
C
C
320912 G01
320912 G02
320912 G03
1ms/DIV
500ns/DIV
500ns/DIV
1.5x Mode Charge Pump Open-
Loop Output Resistance vs
1.5x Mode CPO Voltage
vs Load Current
1x Mode Switch Resistance
vs Temperature
Temperature (1.5V –V )/I
BAT CPO CPO
0.65
0.60
3.2
4.8
4.6
I
= 200mA
V
BAT
V
CPO
= 3V
= 4.2V
C2 = C3 = C4 = 2.2µF
CPO
3.0 C2 = C3 = C4 = 2.2µF
0.55
0.50
2.8
2.6
4.4
4.2
V
= 3.6V
3.6V
BAT
= 3.3V
V
BAT
V
= 3V
BAT
V
BAT
= 3.9V
3.1V
3.2V
3.3V
3.4V
3.5V
0.45
0.40
0.35
2.4
2.2
2.0
4.0
3.8
3.6
–40
–15
10
35
60
85
–40
–15
10
35
60
85
0
100
200
300
400
500
TEMPERATURE (°C)
TEMPERATURE (°C)
LOAD CURRENT (mA)
3209 G05
3209 G06
3209 G07
320912fa
4
LTC3209-1/LTC3209-2
U W
TYPICAL PERFOR A CE CHARACTERISTICS T = 25°C unless otherwise noted
A
2x Mode Charge Pump Open-Loop
Output Resistance vs Temperature
2x Mode CPO Voltage
vs Load Current
DV Shutdown Current
CC
(2V –V )/I
vs DV Voltage
BAT CPO CPO
CC
3.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
5.2
5.1
5.0
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
V
V
= 3V
BAT
CPO
C2 = C3 = C4 = 2.2µF
V
= 3.6V
BAT
= 4.8V
3.4V
3.5V
3.6 C2 = C3 = C4 = 2.2µF
T
= –40°C
= 25°C
A
3.4
3.2
T
A
= 85°C
3.3V
3.2V
3.1V
= 3V
T
3.0
2.8
2.6
A
V
BAT
–40
–15
10
35
60
85
3.9
DV VOLTAGE (V)
4.5
2.7
3
3.3
3.6
4.2
0
100
200
300
400
500
TEMPERATURE (°C)
LOAD CURRENT (mA)
CC
3209 G08
3209 G11
3209 G09
V
Shutdown Current
Voltage
1x Mode No Load V
Current
BAT
1.5x Mode Supply Current
BAT
vs V
vs V
Voltage
vs I
(I
–1.5I
)
BAT
BAT
CPO VBAT
CPO
30
20
10
0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
400
380
360
340
320
300
280
260
240
220
200
V
= 3.6V
DV = 3V
BAT
CC
T
= 85°C
A
T
= 25°C
A
T
= –40°C
A
0
100
200
300
400
500
3.9
4.5
2.7
3
3.3
V
3.6
4.2
2.7
3.0
3.6
3.9
4.2
4.5
3.3
LOAD CURRENT (mA)
V
VOLTAGE (V)
VOLTAGE (V)
BAT
BAT
3209 G14
3209 G12
3209 G13
LTC3209-1 CAM Pin Current
vs CAM Pin Voltage
LTC3209-1 CAM Pin Current
vs Input Code
2x Mode Supply Current
vs I
(I
–2I
)
CPO VBAT
CPO
400
360
320
280
240
200
160
120
80
25
20
15
400
300
200
100
0
V
= 3.6V
V
= 3.6V
V
= 3.6V
BAT
BAT
BAT
10
5
40
0
0
0
A F
1 2 3 4 5 6 7 8 9 B C D E
0
100
200
300
400
500
0
0.2
0.6
CAM PIN VOLTAGE (V)
0.8
0.4
1.0
HEX CODE
LOAD CURRENT (mA)
3209 G23
3209 G15
3209 G22
320912fa
5
LTC3209-1/LTC3209-2
U W
TYPICAL PERFOR A CE CHARACTERISTICS T = 25°C unless otherwise noted
A
LTC3209-2 CAM Pin Current
vs Input Code
LTC3209-1 CAM Pin Dropout
Voltage vs CAM Pin Current
LTC3209-2 CAM Pin Current
vs CAM Pin Voltage
400
360
320
280
220
200
160
120
80
200
160
120
80
200
180
160
140
120
100
80
V
= 3.6V
V
= 3.6V
BAT
V
= 3.6V
BAT
BAT
60
40
40
40
20
0
0
0
0
100
200
300
400
0
0.2
0.4
0.6
0.8
1.0
0 1 2 3 4
5 6 7 8 9 A B C D E F
CAM PIN CURRENT (mA)
CAM PIN VOLTAGE (V)
HEX CODE
3209 G24
3209 G16
3209 G17
LTC3209-2 CAM Pin Dropout
Voltage vs CAM Pin Current
MAIN Pin Current
MAIN Pin Current vs Input Code
vs MAIN Pin Voltage
400
360
320
280
220
200
160
120
80
30
25
28
26
24
22
20
18
16
14
12
10
8
V
= 3.6V
BAT
V
BAT
= 3.6V
20
15
10
5
6
4
2
0
40
V
= 3.6V
BAT
0
0
0
50
100
150
200
0
0.2
0.4
0.6
0.8
1.0
0 10 20 30 40 50 60 70 80 90A0B0C0D0E0 F0 FF
CAM PIN CURRENT (mA)
MAIN PIN VOLTAGE (V)
HEX CODE
3209 G24
3209 G26
3209 G17
MAIN Pin Dropout Voltage
vs MAIN Pin Current
6-LED MAIN Display Efficiency
AUX Pin Current vs Input Code
vs V
BAT
200
180
160
140
120
100
80
16
14
12
10
100
90
80
70
60
50
40
30
20
10
0
V
= 3.6V
V
V
= 3.6V
= 1V
BAT
BAT
AUX
8
6
60
4
2
0
40
6 LEDS AT 15mA/LED
(TYP V AT 15mA = 3.2V)
20
F
0
1
2
0
3
0
5
15
20
25
30
10
3.0
3.4 3.6 3.8
(V)
4.0 4.2 4.4
3209 G21
3.2
MAIN PIN CURRENT (mA)
HEX CODE
V
BAT
3209 G20
3209 G27
320912fa
6
LTC3209-1/LTC3209-2
U
U
U
(LTC3209-1/LTC3209-2)
PI FU CTIO S
CPO (Pin 1/Pin 1): Output of the Charge Pump Used to
Power LEDs. A 2.2µF X5R or X7R ceramic capacitor
should be connected to ground.
CAM1-2 (Pins 11, 12, LTC3209-2): Current Source
Outputs for the CAM1 and CAM2 Display White LEDs. The
LEDs on the two CAM displays can each be set from 0mA
to 200mA in 16 steps via software control and internal
4-bit linear DAC. Two 4-bit registers are available. One is
used to program the high camera current and the second
the low camera current. These registers can be selected
via the serial port or the CAMHL pin. Each output can be
disabled by connecting the output to CPO. Setting data in
REGB to 0 disables both CAM outputs. (See Applications
Information).
MAIN1-6 (Pins 2, 3, 4, 5, 6, 7, LTC3209-1): Current
Source Outputs for the MAIN Display White LEDs. The
LEDs on the MAIN display can be set from 0mA to 28mA
in 256 steps via software control and internal 8-bit linear
DAC.Eachoutputcanbedisabledexternallybyconnecting
the output to CPO. Setting data in REGA to 0 disables all
MAIN outputs.
MAIN1-5 (Pins 2, 3, 4, 5, 6, LTC3209-2): Current Source
OutputsfortheMAINDisplayWhiteLEDs.TheLEDsonthe
MAIN display can be set from 0mA to 28mA in 256 steps
via software control and internal 8-bit linear DAC. Each
outputcanbedisabledexternallybyconnectingtheoutput
to CPO. Setting data in REGA to 0 disables all MAIN
outputs.
CAM (Pin 12, LTC3209-1): Current Source Output for the
CAM Display White LED. The LED on the CAM display can
besetfrom0mAto400mAin16stepsviasoftwarecontrol
and internal 4-bit linear DAC. Two 4-bit registers are
available. One is used to program the high camera current
and the second the low camera current. These registers
can be selected via the serial port or the CAMHL pin. Each
output can be disabled by connecting the output to CPO.
Setting data in REGB to 0 disables the CAM output. (See
Applications Information).
AUX (Pin 8/Pin 7): Current Source Output for the AUX
Display LED. The LED current source can be set from 0mA
to 13.75mA in 4 steps via software control and internal 2-
bit DAC. AUX does not have dropout sensing and cannot
be disabled by connecting to CPO. This pin can also be
used as an I2C controlled general purpose output.
CAMHL(Pin13/Pin13):ThispinselectsCAMhighcurrent
register when asserted high and CAM low current register
when low. The high to low transition automatically resets
the charge pump mode to 1x.
SDA (Pin 14/Pin 14): I2C Data Input for the Serial Port.
Serial data is shifted in one bit per clock to control the
LTC3209-1/LTC3209-2. The logic level is referenced to
DVCC.
VBAT2,1 (Pins9,18/Pins8,18):SupplyVoltagefortheEntire
Device. Two separate pins are used to isolate the charge
pump from the analog sections to reduce noise. Both pins
must be connected together externally and bypassed with
a single 2.2µF low ESR ceramic capacitor close to VBAT1
VBAT2 may require a 0.1µF capacitor.
.
SCL (Pin 15/Pin 15): I2C Clock Input. The logic level for
SCL is referenced to DVCC.
RREF(Pin10/Pin9):Thispincontrolsthemaximumamount
of LED current for all displays. The RREF voltage is 1.23V.
An external 24.3k resistor to ground sets the reference
currentsforalldisplayDACsandsupportcircuitsfornomi-
nalMAINfull-scalecurrentof28mAandtotalCAMfull-scale
current of 400mA. The value for RREF is limited to a range
of 20k to 30k.
C1P, C2P, C1M, C2M (Pins 20, 19, 17, 16/Pins 20, 19,
17, 16): Charge Pump Flying Capacitor Pins. A 2.2µF X7R
or X5R ceramic capacitor should be connected from C1P
to C1M and C2P to C2M.
Exposed Pad (Pin 21/Pin 21): System Ground. Connect
Exposed Pad to PCB ground plane.
DVCC (Pin 11/Pin 10): Supply Voltage for All Digital I/O
Lines. This pin sets the logic reference level of the
LTC3209-1/LTC3209-2. Decouple DVCC to GND with a
0.1µF capacitor. A UVLO circuit on the DVCC pin forces all
registers to all 0s whenever DVCC is below the UVLO
threshold.
320912fa
7
LTC3209-1/LTC3209-2
W
BLOCK DIAGRA
C1P
C1M
C2P
C2M
GND
CPO
850kHz
OSCILLATOR
CHARGE PUMP
ENABLE CP
V
V
BAT1
BAT2
–
+
MAIN1
MAIN2
MAIN3
MAIN4
MAIN5
+
–
6
2
MAIN CURRENT
SOURCES
R
REF
MAIN6
(LTC3209-1)
DV
1.23V
CC
CAM CURRENT
SOURCES
CAM1
CAMHL
CONTROL LOGIC
CAM2
(LTC3209-2)
AUX CURRENT
SOURCE
AUX
MASTER/SLAVE
REG
SDA
SCL
SHIFT REGISTER
320912 BD
320912fa
8
LTC3209-1/LTC3209-2
U
OPERATIO
The LTC3209-1 has 6 MAIN outputs, 1 CAM output and 1
AUX output. The LTC3209-2 has 5 MAIN outputs, 2 CAM
outputs and 1 AUX output.
Soft-Start
Initially, when the part is in shutdown, a weak switch
connectsVBAT1 toCPO.ThisallowsVBAT1 toslowlycharge
the CPO output capacitor and prevent large charging
currents to occur.
Power Management
The LTC3209-1/LTC3209-2 use a switched capacitor
chargepumptoboostCPOtoasmuchas2timestheinput
voltage up to 5.1V. The part starts up in 1x mode. In this
mode, VBAT is connected directly to CPO. This mode
provides maximum efficiency and minimum noise. The
LTC3209-1/LTC3209-2 will remain in 1x mode until a
MAIN or CAM LED current source drops out. Dropout
occurswhenacurrentsourcevoltagebecomestoolowfor
the programmed current to be supplied. When dropout is
detected, the LTC3209-1/LTC3209-2 will switch into 1.5x
mode. The CPO voltage will then start to increase and will
attempt to reach 1.5x VBAT up to 4.6V. Any subsequent
dropout will cause the part to enter the 2x mode. The CPO
voltage will attempt to reach 2x VBAT up to 5.1V. The part
willberesetto1xmodewheneveraDACdatabitisupdated
via the I2C port or on the falling edge of the CAMHL signal.
The LTC3209-1/LTC3209-2 also employs a soft-start
feature on its charge pump to prevent excessive inrush
current and supply droop when switching into the step-up
modes. The current available to the CPO pin is increased
linearly over a typical period of 125µs. Soft-start occurs at
the start of both 1.5x and 2x mode changes.
Charge Pump Strength
When the LTC3209-1/LTC3209-2 operate in either 1.5x
mode or 2x mode, the charge pump can be modeled as a
Thevenin-equivalent circuit to determine the amount of
current available from the effective input voltage and
effective open-loop output resistance, ROL (Figure 1).
ROL is dependent on a number of factors including the
switching term, 1/(2fOSC • CFLY), internal switch resis-
tances and the nonoverlap period of the switching circuit.
However, for a given ROL, the amount of current available
will be directly proportional to the advantage voltage of
1.5VBAT -CPOfor1.5xmodeand2VBAT-CPOfor2xmode.
A 2-phase nonoverlapping clock activates the charge
pump switches. In the 2x mode the flying capacitors are
charged on alternate clock phases from VBAT to minimize
input current ripple and CPO voltage ripple. In 1.5x mode
the flying capacitors are charged in series during the first
clock phase and stacked in parallel on VBAT during the
secondphase. Thissequenceofcharginganddischarging
the flying capacitors continues at a constant frequency of
850kHz.
R
OL
+
+
CPO
1.5VBAT OR 2VBAT
–
–
320912 F01
The currents delivered by the LED current sources are
controlledbyanassociatedDAC.EachDACisprogrammed
via the I2C port.
Figure 1. Charge Pump Thevenin Equivalent Open-Loop Circuit
320912fa
9
LTC3209-1/LTC3209-2
U
OPERATIO
Consider the example of driving white LEDs from a 3.1V
supply. If the LED forward voltage is 3.8V and the current
sources require 100mV, the advantage voltage for 1.5x
mode is 3.1V • 1.5 – 3.8V – 0.1V or 750mV. Notice that if
the input voltage is raised to 3.2V, the advantage voltage
jumps to 900mV—a 20% improvement in available
strength.
Notice that the advantage voltage in this case is
3.1V • 2 – 3.8V – 0.1V = 2.3V. ROL is higher in 2x mode but
asignificantoverallincreaseinavailablecurrentisachieved.
Typical values of ROL as a function of temperature are
shown in Figures 2 and 3.
Shutdown Current
From Figure 1, for 1.5x mode the available current is given
by:
Shutdown occurs when all the current source data bits
have been written to zero or when DVCC is below the DVCC
UVLO threshold.
1.5VBAT – VCPO
IOUT
=
Although the LTC3209-1/LTC3209-2 is designed to have
very low shutdown current, it will draw about 3µA from
VBAT when in shutdown. Internal logic ensures that the
LTC3209-1/LTC3209-2 is in shutdown when DVCC is
grounded. Note, however that all of the logic signals that
arereferencedtoDVCC (SCL, SDA, CAMHL)willneedtobe
at DVCC or below (i.e., ground) to avoid violation of the
absolute maximum specifications on these pins.
ROL
For 2x mode, the available current is given by:
2VBAT – VCPO
IOUT
=
ROL
3.2
3.8
V
= 3V
V
V
= 3V
BAT
CPO
BAT
CPO
V
= 4.2V
= 4.8V
3.0 C2 = C3 = C4 = 2.2µF
3.6 C2 = C3 = C4 = 2.2µF
2.8
2.6
3.4
3.2
2.4
2.2
2.0
3.0
2.8
2.6
–40
–15
10
35
60
85
–40
–15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
3209 G06
3209 G08
Figure 2. Typical 1.5x R vs Temperature
Figure 3. Typical 2x R vs Temperature
OL
OL
320912fa
10
LTC3209-1/LTC3209-2
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OPERATIO
Serial Port
Camera Current Sources
The microcontroller compatible I2C serial port provides all
of the command and control inputs for the LTC3209-1/
LTC3209-2. Data on the SDA input is loaded on the rising
edge of SCL. D7 is loaded first and D0 last. There are three
data registers and one address register. Once all address
bits have been clocked into the address register acknowl-
edge occurs. After the data registers have been written a
load pulse is created after the stop bit. The load pulse
transfersallofthedataheldinthedataregisterstotheDAC
registers. At this point the LED current will be changed to
the new settings. The serial port uses static logic registers
so there is no minimum speed at which it can be operated.
LTC3209-1
There is one CAM current source. This current source has
a 4-bit linear DAC for current control. The output current
range is 0mA to 400mA in 16 steps (RREF = 24.3k).
The current source is disabled when the block receives an
all zero data word. The supply current for the block is
reduced to zero. In addition, the LED output can be
connectedtoCPOtoturnoffthecurrentsourceoutputand
reduceoperatingcurrenttotypically10µA.Thispincannot
be allowed to float if unused since dropout will be errone-
ously detected.
LTC3209-2
MAIN Current Sources
TherearetwoCAMcurrentsources.Thesecurrentsources
have a 4-bit linear DAC for current control. The output
current range of each current source is 0mA to 200mA in
16 steps (RREF = 24.3k).
LTC3209-1
TherearesixMAINcurrentsources.Thesecurrentsources
have an 8-bit linear DAC for current control. For RREF
24.3k, the output current range is 0mA to 28mA in 256
steps.
=
The current sources are disabled when the block receives
an all zero data word. The supply current for the block is
reduced to zero. In addition unused LED outputs can be
connectedtoCPOtoturnoffthecurrentsourceoutputand
reduce the operating current to typically 10µA. These pins
cannot be allowed to float if unused since dropout will be
erroneously detected.
The current sources are disabled when a block receives an
all zero data word. The supply current for that block is
reduced to zero. In addition unused LED outputs can be
connectedtoCPOtoturnoffthecurrentsourceoutputand
reduce the operating current to typically 10µA.
LTC3209-2
Auxiliary Current Source
TherearefiveMAINcurrentsources.Thesecurrentsources
have an 8-bit linear DAC for current control. For RREF
24.3k, the output current range is 0mA to 28mA in 256
steps.
There is one AUX current source. This current source has
a 2-bit Linear DAC for current control. The output current
range is 0mA to 13.75mA in 4 steps (OFF, 33%, 67%,
100%). The AUX output does not have dropout detection
and cannot be disabled when connected to CPO.
=
The current sources are disabled when a block receives an
all zero data word. The supply current for that block is
reduced to zero. In addition unused LED outputs can be
connectedtoCPOtoturnoffthecurrentsourceoutputand
reduce the operating current to typically 10µA.
The current source is disabled when the block receives an
all zero data word and the supply current for the block is
reduced to zero. This output can also be used as an I2C
controlled digital open-drain general purpose output.
320912fa
11
LTC3209-1/LTC3209-2
U
OPERATIO
A 24.3k, 1% resistor provides full-scale currents of 28mA
fortheMAIN;400mA(total)currentforCAMand13.75mA
for AUX current sources.
CAMHL
The CAMHL pin quickly selects the camera high register
for flash applications without reaccessing the I2C port.
When low the CAM current range will be controlled by the
camera low 4-bit register. When CAMHL is asserted high
the current range will be set by the camera high 4-bit
register. The dropout delay is reduced from 150ms to 2ms
when CAMHL is asserted high so that the charge pump
can quickly change modes if required. When CAMHL
isassertedfromhightolowthechargepumpmodeisreset
to 1x.
This input is protected against shorts to ground or
low value resistors <10k. When a fault is detected the
reference current amplifier is current limited. In addition
the current source outputs and charge pump are disabled.
Mode Switching
TheLTC3209-1/LTC3209-2willautomaticallyswitchfrom
1x mode to 1.5x mode and subsequently to 2x mode
whenever a dropout condition is detected at an LED pin.
Dropout occurs when a current source voltage becomes
too low for the programmed current to be supplied. When
switching modes the mode change will not occur unless
dropout has existed for 150ms. This delay will allow the
LEDstowarmupandachievethefinalLEDforwardvoltage
value. The dropout delay can be reduced to 2ms by
programming the Drop2ms bit C2 in the REGC register or
when the CAMHL pin is switched high when controlling
the CAM LEDs.
Thermal Protection
The LTC3209-1/LTC3209-2 have built-in overtemperature
protection. At internal die temperatures of around 150°C
thermal shutdown will occur. This will disable all of the
current sources and charge pump until the die has cooled
by about 15°C. This thermal cycling will continue until the
fault has been corrected.
RREF Current Set Resistor
The current set resistor is connected between the RREF pin
and ground. This resistor sets the full-scale current for all
three displays (MAIN, CAM and AUX) according to the
following equations:
The mode will automatically switch back to 1x whenever a
data bit is updated via the I2C port or when CAMHL
switches from high to low. If the part is forced into either
1.5x mode or 2x mode to operate as a fixed voltage power
supply over I2C, no mode switching will occur until an I2C
update is given.
1.23V
RREF
MAIN =
CAM =
CAM =
AUX =
•550
•7900
•3950
•272
1.23V
RREF
(LTC3209-1)
(LTC3209-2)
1.23V
RREF
1.23V
RREF
320912fa
12
LTC3209-1/LTC3209-2
U
OPERATIO
D A U X 0
D A U X 1
D R O P 2 M S
S C A M H I L O
D T H 1
D T H 2
F O R C E I P 5
F O R C E 2 X
320912fa
13
LTC3209-1/LTC3209-2
U
OPERATIO
REGA, MAIN LED 8-Bit DAC Data
MSB
LSB
A0
A7
A6
A5
A4
A3
A2
A1
MAIN D7
MAIN D6
MAIN D5
MAIN D4
MAIN D3
MAIN D2
MAIN D1
MAIN D0
REGB, CAMERA LED 4-Bit High and 4-Bit Low DAC Data
MSB
B7
HIGH BITS
LSB
B4
MSB
B3
LOW BITS
LSB
B0
B6
B5
B2
B1
CAM D3
CAM D2
CAM D1
CAM D0
CAM D3
CAM D2
CAM D1
CAM D0
REGC, AUX Data and Option Byte
MSB
LSB
C0
C7
C6
C5
C4
C3
C2
C1
Force2x
Force1p5
Dth2
Dth1
Scamhilo
Drop2ms
DAUX1
DAUX0
DAUX0
AUX DAC Data (LSB)
AUX DAC Data (MSB)
DAUX1
Drop2ms
1
0
Changes Dropout Time from 150ms to 2ms
Dropout Time is 150ms Unless CAMHL is Enabled and High
Scamhilo
1
0
Selects CAM High Register, Disables CAMHL Pin
Selects CAM Low Register, Enables CAMHL Pin
Dth1
0
0
Must Always be 0 (Test Mode)
Must Always be 0 (Test Mode)
Dth2
Force1p5
1
0
Forces Charge Pump into 1.5x Mode, CPO Regulates at 4.6V
Enables Mode Logic to Control Mode Changes Based on Dropout Signal
Force2x
1
0
Forces Charge Pump into 2x Mode, Overrides Force1p5 Signal, CPO Regulates at 5.1V
Enables Mode Logic to Control Mode Changes Based on Dropout Signal
I2C Interface
Bus Speed
The I2C port is designed to be operated at speeds of up to
400kHz. It has built-in timing delays to ensure correct
operation when addressed from an I2C compliant master
device. It also contains input filters designed to suppress
glitches should the bus become corrupted.
The LTC3209-1/LTC3209-2 communicates with a host
(master) using the standard I2C 2-wire interface. The
Timing Diagram (Figure 5) shows the timing relationship
of the signals on the bus. The two bus lines, SDA and SCL,
must be high when the bus is not in use. External pull-up
resistors or current sources, such as the LTC1694 SMBus
accelerator, are required on these lines.
The LTC3209-1/LTC3209-2 is a receive-only (slave)
device.
320912fa
14
LTC3209-1/LTC3209-2
U
OPERATIO
START and STOP Conditions
Bus Write Operation
Abus-mastersignalsthebeginningofacommunicationto
a slave device by transmitting a START condition.
The master initiates communication with the LTC3209-1/
LTC3209-2 with a START condition and a 7-bit address
followed by the Write Bit R/W = 0. If the address matches
that of the LTC3209-1/LTC3209-2, the part returns an
Acknowledge. The master should then deliver the most
significant data byte. Again the LTC3209-1/LTC3209-2
acknowledges and cycle is repeated two more times for a
total of one address byte and three data bytes. Each data
byte is transferred to an internal holding latch upon the
return of an Acknowledge. After all three data bytes have
been transferred to the LTC3209-1/LTC3209-2, the
master may terminate the communication with a STOP
condition. Alternatively, a REPEAT-START condition can
be initiated by the master and another chip on the I2C bus
can be addressed. This cycle can continue indefinitely and
the LTC3209-1/LTC3209-2 will remember the last input of
valid data that it received. Once all chips on the bus
have been addressed and sent valid data, a global STOP
condition can be sent and the LTC3209-1/LTC3209-2 will
update all registers with the data that it had received.
In certain circumstances the data on the I2C bus may
become corrupted. In these cases the LTC3209-1/
LTC3209-2respondsappropriatelybypreservingonlythe
last set of complete data that it has received. For example,
assumetheLTC3209-1/LTC3209-2hasbeensuccessfully
addressed and is receiving data when a STOP condition
mistakenlyoccurs.TheLTC3209-1/LTC3209-2willignore
this STOP condition and will not respond until a new
START condition, correct address, new set of data and
STOP condition are transmitted.
A START condition is generated by transitioning SDA from
high to low while SCL is high. When the master has
finished communicating with the slave, it issues a STOP
condition by transitioning SDA from low to high while SCL
is high. The bus is then free for communication with
another I2C device.
Byte Format
Each byte sent to the LTC3209-1/LTC3209-2 must be
8 bits long followed by an extra clock cycle for the
AcknowledgebittobereturnedbytheLTC3209-1/LTC3209-
2. The data should be sent to the LTC3209-1/LTC3209-2
most significant bit (MSB) first.
Acknowledge
The Acknowledge signal is used for handshaking between
the master and the slave. An Acknowledge (active low)
generated by the slave (LTC3209-1/LTC3209-2) lets the
master know that the latest byte of information was
received. The Acknowledge related clock pulse is
generated by the master. The master releases the SDA
line (high) during the Acknowledge clock cycle. The
slave-receiver must pull down the SDA line during the
Acknowledge clock pulse so that it remains a stable low
during the high period of this clock pulse.
Slave Address
The LTC3209-1/LTC3209-2 responds to only one 7-bit
address which has been factory programmed to 0011011.
The eighth bit of the address byte (R/W) must be 0 for the
LTC3209-1/LTC3209-2torecognizetheaddresssinceitis
a write only device. This effectively forces the address to
be 8 bits long where the least significant bit of the address
is 0. If the correct seven bit address is given but the R/W
bit is 1, the LTC3209-1/LTC3209-2 will not respond.
Likewise, if the LTC3209-1/LTC3209-2 was previously
addressed and sent valid data but not updated with a
STOP, it will respond to any STOP that appears on the bus
with only one exception, independent of the number of
REPEAT-STARTs that have occurred. If a REPEAT-START
is given and the LTC3209-1/LTC3209-2 successfully
acknowledges its address, it will not respond to a STOP
until all bytes of the new data have been received
and acknowledged.
320912fa
15
LTC3209-1/LTC3209-2
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APPLICATIO S I FOR ATIO
VBAT, CPO Capacitor Selection
value of CCPO controls the amount of output ripple, the
value of CVBAT controls the amount of ripple present at
the input pin (VBAT). The LTC3209-1/LTC3209-2 input
current will be relatively constant while the charge pump
is either in the input charging phase or the output
charging phase but will drop to zero during the clock
nonoverlap times. Since the nonoverlap time is small
(~25ns), these missing “notches” will result in only a
small perturbation on the input power supply line. Note
that a higher ESR capacitor such as tantalum will have
higher input noise due to the higher ESR. Therefore,
ceramic capacitors are recommended for low ESR. Input
noise can be further reduced by powering the LTC3209-
1/LTC3209-2 through a very small series inductor as
shown in Figure 6. A 10nH inductor will reject the fast
current notches, thereby presenting a nearly constant
current load to the input power supply. For economy, the
10nH inductor can be fabricated on the PC board with
about 1cm (0.4") of PC board trace.
The style and value of the capacitors used with the
LTC3209-1/LTC3209-2 determine several important
parameterssuchasregulatorcontrolloopstability, output
ripple, charge pump strength and minimum start-up time.
To reduce noise and ripple, it is recommended that low
equivalent series resistance (ESR) ceramic capacitors are
used for both CVBAT and CCPO. Tantalum and aluminum
capacitors are not recommended due to high ESR.
The value of CCPO directly controls the amount of output
ripple for a given load current. Increasing the size of CCPO
will reduce output ripple at the expense of higher start-up
current. The peak-to-peak output ripple of the 1.5x mode
is approximately given by the expression:
IOUT
3fOSC •CCPO
VRIPPLE(P-P)
=
Where fOSC is the LTC3209-1/LTC3209-2 oscillator
frequency or typically 850kHz and CCPO is the output
storage capacitor.
VBAT
LTC3209-1
LTC3209-2
The output ripple in 2x mode is very small due to the fact
that load current is supplied on both cycles of the clock.
GND
320912 F06
Both style and value of the output capacitor can signifi-
cantlyaffectthestabilityoftheLTC3209-1/LTC3209-2. As
shown in the Block Diagram, the LTC3209-1/LTC3209-2
use a control loop to adjust the strength of the charge
pump to match the required output current. The error
signaloftheloopisstoreddirectlyontheoutputcapacitor.
The output capacitor also serves as the dominant pole for
the control loop. To prevent ringing or instability, it is
important for the output capacitor to maintain at least 1µF
of capacitance over all conditions.
Figure 6. 10nH Inductor Used for Input Noise Reduction
(Approximately 1cm of Board Trace)
Flying Capacitor Selection
Warning: Polarized capacitors such as tantalum or
aluminumshouldneverbeusedfortheflyingcapacitors
since their voltage can reverse upon start-up of the
LTC3209-1/LTC3209-2. Ceramic capacitors should
always be used for the flying capacitors.
In addition, excessive output capacitor ESR will tend to
degrade the loop stability. If the output capacitor has
160mΩ or more of ESR, the closed-loop frequency
responsewillceasetorolloffinasimpleone-polefashion
and poor load transient response or instability may
occur. Multilayer ceramic chip capacitors typically have
exceptional ESR performance. MLCCs combined with a
tight board layout will result in very good stability. As the
The flying capacitors control the strength of the charge
pump. In order to achieve the rated output current it is
necessary to have at least 1.6µF of capacitance for each of
theflyingcapacitors. Capacitorsofdifferentmaterialslose
their capacitance with higher temperature and voltage at
different rates. For example, a ceramic capacitor made of
X7R material will retain most of its capacitance from
–40°C to 85°C whereas a Z5U or Y5V style capacitor will
320912fa
16
LTC3209-1/LTC3209-2
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APPLICATIO S I FOR ATIO
The following guidelines should be followed when design-
ing a PCB layout for the LTC3209.
lose considerable capacitance over that range. Z5U and
Y5V capacitors may also have a very poor voltage
coefficient causing them to lose 60% or more of their
capacitance when the rated voltage is applied. Therefore,
when comparing different capacitors, it is often more
appropriate to compare the amount of achievable
capacitance for a given case size rather than comparing
the specified capacitance value. For example, over rated
voltage and temperature conditions, a 1µF, 10V, Y5V
ceramic capacitor in a 0603 case may not provide any
more capacitance than a 0.22µF, 10V, X7R available in the
same case. The capacitor manufacturer’s data sheet
should be consulted to determine what value of capacitor
is needed to ensure minimum capacitances at all
temperatures and voltages.
• The Exposed Pad should be soldered to a large copper
planethatisconnectedtoasolid,lowimpedanceground
plane using plated, through-hole vias for proper heat
sinking and noise protection.
• Input and output capacitors (C1 and C4) must be placed
close to the part.
• The flying capacitors (C2 and C3) must be placed close
to the part. The traces running from the pins to the
capacitor pads should be as wide as possible.
• VBAT, CPO traces must be made wide to minimize
inductance and handle the high currents.
• LEDpadsmustbelargeandconnectedtootherlayersof
metal to ensure proper heat sinking.
Table 1 shows a list of ceramic capacitor manufacturers
and how to contact them:
Table 1. Recommended Capacitor Vendors
ALL VIAS
AVX
Kemet
www.avxcorp.com
www.kemet.com
www.murata.com
www.t-yuden.com
www.vishay.com
LABELED V
BAT
ARE CONNECTED TO
PLANE LAYER
GND
PLANE
LAYER
V
BAT
C2
Murata
ALL VIAS
V
BAT
LABELED GND
ARE CONNECTED TO
GND PLANE LAYER
Taiyo Yuden
Vishay
C3
C1
CPO
Layout Considerations and Noise
GND
V
BAT1
SOLDER SIDE
COMPONENT
C4
Due to the high switching frequency and the transient
currents produced by the LTC3209-1/LTC3209-2, careful
board layout is necessary. A true ground plane and short
connections to all capacitors will improve performance
and ensure proper regulation under all conditions.
GND
GND
DV
CC
C5
R
REF
The flying capacitor pins C1P, C2P, C1M and C2M will
have high edge rate waveforms. The large dv/dt on these
pins can couple energy capacitively to adjacent PCB runs.
Magnetic fields can also be generated if the flying capaci-
tors are not close to the LTC3209-1/LTC3209-2 (i.e., the
loopareaislarge). Todecouplecapacitiveenergytransfer,
a Faraday shield may be used. This is a grounded PCB
trace between the sensitive node and the LTC3209-1/
LTC3209-2pins. ForahighqualityACground, itshouldbe
returned to a solid ground plane that extends all the way to
the LTC3209-1/LTC3209-2.
V
V PLANE
BAT
LAYER
BAT2
GND
R1
V
BAT
C6
GND
GND
3209 F07
Figure 7. PC Board Layout Example (LTC3209-1)
320912fa
17
LTC3209-1/LTC3209-2
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APPLICATIO S I FOR ATIO
Power Efficiency
In 1.5x boost mode, the efficiency is similar to that of a
linear regulator with an effective input voltage of 1.5 times
the actual input voltage. This is because the input current
fora1.5xchargepumpisapproximately1.5timestheload
current.Inanideal1.5xchargepump,thepowerefficiency
would be given by:
To calculate the power efficiency (η) of a white LED driver
chip, the LED power should be compared to the input
power. The difference between these two numbers repre-
sents lost power whether it is in the charge pump or the
current sources. Stated mathematically, the power effi-
ciency is given by:
V
• ILED
(
)
PLED
VLED
VBAT
LED
η
=
=
=
IDEAL
P
V
•
(1.5)
•
ILED
1.5
(
•
(
)
)
IN
BAT
P
P
LED
η =
(1.5x Mode)
IN
Similarly, in 2x boost mode, the efficiency is similar to that
of a linear regulator with an effective input voltage of 2
times the actual input voltage. In an ideal 2x charge pump,
the power efficiency would be given by:
TheefficiencyoftheLTC3209-1/LTC3209-2dependsupon
the mode in which it is operating. Recall that the
LTC3209-1/LTC3209-2 operates as a pass switch,
connecting VBAT to CPO, until dropout is detected at the
ILED pin. This feature provides the optimum efficiency
available for a given input voltage and LED forward
voltage. When it is operating as a switch, the efficiency is
approximated by:
V
• ILED
(
)
PLED
VLED
VBAT
LED
η
=
=
=
IDEAL
P
V
•
(2)
•
ILED
2
•
(
)
(
)
IN
BAT
(2x Mode)
V
•
•
ILED
(
(
)
)
PLED
VLED
VBAT
LED
η =
=
=
Thermal Management
(1x Mode)
P
V
IBAT
IN
BAT
For higher input voltages and maximum output current,
there can be substantial power dissipation in the
LTC3209-1/LTC3209-2. If the junction temperature in-
creases above approximately 150°C the thermal shut-
down circuitry will automatically deactivate the output
current sources and charge pump. To reduce maximum
junctiontemperature,agoodthermalconnectiontothePC
board is recommended. Connecting the Exposed Pad to a
ground plane and maintaining a solid ground plane under
the device will reduce the thermal resistance of the pack-
age and PC board considerably.
since the input current will be very close to the sum of the
LED currents.
At moderate to high output power, the quiescent current
oftheLTC3209-1/LTC3209-2isnegligibleandtheexpres-
sion above is valid.
Once dropout is detected at the LED pin, the LTC3209-1/
LTC3209-2 enables the charge pump in 1.5x mode.
320912fa
18
LTC3209-1/LTC3209-2
U
PACKAGE DESCRIPTIO
UF Package
20-Lead Plastic QFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1710)
0.70 ±0.05
4.50 ± 0.05
3.10 ± 0.05
2.45 ± 0.05
(4 SIDES)
PACKAGE OUTLINE
0.25 ±0.05
0.50 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
BOTTOM VIEW—EXPOSED PAD
PIN 1 NOTCH
R = 0.115
TYP
R = 0.30 TYP
0.75 ± 0.05
4.00 ± 0.10
(4 SIDES)
19 20
0.38 ± 0.10
PIN 1
TOP MARK
(NOTE 6)
1
2
2.45 ± 0.10
(4-SIDES)
(UF20) QFN 10-04
0.200 REF
0.25 ± 0.05
0.50 BSC
0.00 – 0.05
NOTE:
1. DRAWING IS PROPOSED TO BE MADE A JEDEC PACKAGE OUTLINE MO-220
VARIATION (WGGD-1)—TO BE APPROVED
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON THE TOP AND BOTTOM OF PACKAGE
320912fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
19
LTC3209-1/LTC3209-2
U
TYPICAL APPLICATIO
4 LED MAIN, 1 LED SUB, 400mA CAM LED Controller Plus Regulated Output
C2
2.2µF
C3
2.2µF
4x25mA
MAIN
C4
2.2µF
1x15mA 1x400mA
AUX CAM
5.1V, 2x MODE
4.6V, 1.5x MODE
C1P C1M C2P C2M
V
BAT
CPO
V
BAT1
V
BAT2
C1
2.2µF
C6
LTC3209-1
SPEAKER
0.1µF
MAIN1
MAIN2
MAIN3
MAIN4
MAIN5
MAIN6
DV
DV
CC
CC
EN
C5
0.1µF
SCL
2
I C
SDA
AUX
TORCH FLASH
CAMHL
CAM
3209 TA03
R
REF
GND
R1
24.3k
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PART NUMBER
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COMMENTS
Up to 6 White LEDs, V : 2.7V to 4.5V, V
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Q
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= 5V, I = 5mA,
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≤1µA, 10-Lead MS Package
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Multidisplay LED Controller
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SD
(4mm × 4mm) QFN Package
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92% Efficiency, 400mA Continuous Output Current. Up to 11 White
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High Current Software Configurable Multidisplay
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95% Efficiency, V : 2.9V to 4.5V, V
: 5.5V, I = 280µA,
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I
< 1µA, (5mm × 5mm) QFN-32 Package
SD
500mA Camera LED Charge Pump
94% Efficiency, V : 2.9V to 4.5V, I = 300µA, I < 2.5µA, 500mA
IN Q SD
Output Current, 10-Lead (3mm × 3mm) DFN Package
700mA Low Noise High Current LED Charge Pump
1A Low Noise High Current White LED Driver
600mA Low Noise Multi-LED Camera Light
V : 2.9V to 4.4V, V = 5.5V, I = 300µA, I < 2.5µA
IN
OUT(MAX)
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SD
(3mm × 3mm) DFN Package
93% Efficiency, 1A Output Current, 12-Lead (3mm × 4mm)
DFN Package, Independent Low/High Current Programming
V : 2.9V to 4.4V, I = 400µA, Four Outputs, (3mm × 3mm) 16-Lead
IN
Q
DFN Package
500mA (I ), 1MHz to 1.6MHz Spread Spectrum
85% Efficiency, V : 3.1V to 5.5V, V : 0.9V to 1.6V, I = 9µA,
OUT
IN
OUT
Q
Step-Down Charge Pump
I
≤1µA, 10-Lead MS Package
SD
600mA (I ), 2MHz Synchronous Buck-Boost
95% Efficiency, V : 2.5V to 5.5V, V
SD
= 2.5V, I = 25µA,
OUT
IN
OUT(MIN) Q
DC/DC Converter
I
≤1µA, 10-Lead MS Package
ThinSOT is a trademark of Linear Technology Corporation.
320912fa
LT 0506 REV A • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
20
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2005
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