FEATURES
■
■
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LTC3208
High Current Software
Configurable Multidisplay
LED Controller
DESCRIPTIO
The LTC
®
3208 is a highly integrated multidisplay LED
controller. The part contains a 1A high efficiency, low noise
charge pump to provide power to the MAIN, SUB, RGB, CAM
and AUX LED displays. The LTC3208 requires only small
ceramic capacitors and one current set resistor to form a
complete LED power supply and current controller.
The maximum display currents are set by a single ex-
ternal resistor. Current for each LED is controlled by a
precision internal current source. Dimming and On/Off
for all displays is achieved via the I
2
C serial interface.
256 brightness levels are available for the MAIN and SUB
displays. 16 levels are available for the RGB and CAM
displays. Four AUX current sources can be independently
assigned via the I
2
C port to the CAM, SUB, MAIN or AUX
DAC controlled displays.
The LTC3208 charge pump optimizes efficiency based
on the voltage across the LED current sources. The part
powers up in 1x mode and will automatically switch to
boost mode whenever any enabled LED current source
begins to enter dropout. The first dropout switches the
part into 1.5x mode and a subsequent dropout switches
the LTC3208 into 2x mode. The part is available in a small
5mm
×
5mm 32-lead QFN package.
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1x/1.5x/2x Charge Pump Provides Up to 95%
Efficiency
Up to 1A Total Output Current
17 Current Sources Available as MAIN, SUB, RGB,
CAM and AUX LED Drivers
LED ON/OFF, Brightness Level and Display
Configuration Programmable Using 2-Wire I
2
C™
Interface
Low Noise Constant Frequency Operation with Flying
Capacitor Edge Rate Control
Automatic Charge Pump Mode Switching
Internal Soft-Start Limits Inrush Current During
Startup and Mode Switching
Open/Shorted LED Protection
Short-Circuit/Thermal Protection
256 Brightness States for MAIN and SUB Displays
4096 Color Combinations for the RGB Display
5mm × 5mm 32-Lead QFN Plastic Package
APPLICATIO S
■
Video/Camera Phones with QVGA + Displays
, LTC and LT are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents including
6411531.
TYPICAL APPLICATIO
C2
2.2
m
F
C3
2.2
m
F
V
BAT
C1
4.7
m
F
EFFICIENCY (P
LED
/P
IN
) (%)
C1P C1M C2P C2M
V
BAT1,2,3
CPO
C4
4.7
m
F
4
2
4
3
4
MAIN
SUB
CAMERA
RGB
AUX
LTC3208
MAIN1-4
I
2
C
ENABLE DISABLE
LOW HI
SCL/SDA
ENRGBS
CAMHL
R
REF
24.3k
1%
SUB1-2
CAM1-4
RGB
AUX1-4
GND
U
U
U
4-LED MAIN Display
Efficiency vs Input Voltage
100
90
80
70
60
50
40
30
20 4 LEDs AT 15mA/LED
10 (TYP V
F
AT 15mA = 3.2V)
T
A
= 25°C
0
3.0 3.2 3.4 3.6 3.8
V
BAT
(V)
4.0
4.2
4.4
3208 TA01a
3208 TA01b
3208fa
1
LTC3208
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
ENRGBS
V
BAT1
C1M
C2M
GND
CPO
C1P
C2P
V
BAT
, DV
CC
, CPO to GND ................................– 0.3 to 6V
SDA, SCL, ENRGBS, CAMHL .....– 0.3V to (DV
CC
+ 0.3V)
I
CPO
(Note 2) ............................................................1.3A
I
MAIN1-4
, I
SUB1-2
(Note 3) .......................................33mA
I
RED
, I
GRN
, I
BLUE
(Note 3) .......................................33mA
I
CAM1-4
, I
AUX1-4
(Note 3) ......................................120mA
CPO, R
REF
Short-Circuit Duration .................... Indefinite
Operating Temperature Range (Note 4) .. – 40°C to 85°C
Storage Temperature Range.................. – 65°C to 125°C
32 31 30 29 28 27 26 25
CAM1 1
CAM2 2
CAM3 3
CAM4 4
AUX1 5
AUX2 6
AUX3 7
AUX4 8
9 10 11 12 13 14 15 16
MAIN1
CAMHL
MAIN2
SDA
SCL
V
BAT3
D
VCC
R
REF
33
24 V
BAT2
23 RED
22 GRN
21 BLUE
20 SUB1
19 SUB2
18 MAIN4
17 MAIN3
UH PACKAGE
32-LEAD (5mm
×
5mm) QFN
EXPOSED PAD IS GND (PIN 33)
MUST BE SOLDERED TO PCB
T
JMAX
= 125°C,
θ
JA
= 34°C/W
ORDER PART NUMBER
LTC3208EUH
UH PART MARKING
3208
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.
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BAT
= 3.6V, DV
CC
= 3V, ENRGBS = Hi, R
REF
= 24k, C2 = C3 = 2.2µF,
C1 = C4 = 4.7µF, unless otherwise noted.
PARAMETERS
V
BAT
Operating Voltage
I
VBAT
Operating Current
CONDITIONS
●
ELECTRICAL CHARACTERISTICS
MIN
2.9
TYP
280
4.7
7
MAX
4.5
UNITS
V
µA
mA
mA
V
µA
V
V
µA
V
k
mA
µA
%
mV
3208fa
I
CPO
= 0, 1x Mode, LEDs Disabled
I
CPO
= 0, 1.5x Mode
I
CPO
= 0, 2x Mode
●
DV
CC
Operating Voltage
DV
CC
Operating Current
V
BAT
UVLO Threshold
DV
CC
UVLO Threshold
V
BAT
Shutdown Current
R
REF
VR
REF
RR
REF
White LED Current (MAIN1-4, SUB1-2), 8-Bit Linear DACs
Full-Scale LED Current
Minimum (1LSB) LED Current
LED Current Matching
LED Dropout Voltage
1.5
1.5
1
3.2
DV
CC
= 1.8V, Serial Port Idle
●
5.5
1
DV
CC
= 1.8V
●
Reference Resistor Range
MAIN, SUB = 1V
MAIN, SUB = 1V
Any Two MAIN or SUB Outputs, 50% FS
I
LED
= FS
●
●
1.195
22
25.3
1.215
1.235
30
29.7
27.5
108
1
180
2
U
W
U
U
W W
W
LTC3208
ELECTRICAL CHARACTERISTICS
PARAMETERS
CONDITIONS
●
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BAT
= 3.6V, DV
CC
= 3V, ENRGBS = Hi, R
REF
= 24k, C2 = C3 = 2.2µF,
C1 = C4 = 4.7µF, unless otherwise noted.
MIN
92.5
TYP
102.5
6.96
1
540
26
1.73
1
140
104.9
28.1
0.24
0.32
0.46
0.63
0.89
1.22
1.74
2.42
3.47
4.73
6.7
9.47
13.56
19.05
27.06
0.35
2
2.2
4.53
5.02
0.9
MAX
112.5
UNITS
mA
mA
%
mV
mA
mA
%
mV
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
White LED Current (CAM1-4), 4-Bit Linear DAC
Full-Scale LED Current
CAM = 1V
Minimum (1LSB) LED Current
CAM = 1V
LED Current Matching
Any Two CAM Outputs, 50% FS
LED Dropout Voltage
I
LED
= FS
White LED Current (AUX1-4, AUX Outputs Assigned to AUX DAC), 4-Bit Linear DAC
Full-Scale LED Current
AUX = 1V
Minimum (1LSB) LED Current
AUX = 1V
LED Current Matching
LED Dropout Voltage
Two AUX Outputs, 50% FS
I
LED
= FS
●
23
28.5
Full-Scale AUX LED Current
AUX Connected to CAM DAC, AUX = 1V
Full-Scale AUX LED Current
AUX Connected to SUB or MAIN DAC, AUX = 1V
RGB LED Current (RED, GREEN, BLUE), 4-Bit Exponential DAC
DAC Code 0001
RED, GREEN, BLUE = 1V
DAC Code 0010
RED, GREEN, BLUE = 1V
DAC Code 0011
RED, GREEN, BLUE = 1V
DAC Code 0100
RED, GREEN, BLUE = 1V
DAC Code 0101
RED, GREEN, BLUE = 1V
DAC Code 0110
RED, GREEN, BLUE = 1V
DAC Code 0111
RED, GREEN, BLUE = 1V
DAC Code 1000
RED, GREEN, BLUE = 1V
DAC Code 1001
RED, GREEN, BLUE = 1V
DAC Code 1010
RED, GREEN, BLUE = 1V
DAC Code 1011
RED, GREEN, BLUE = 1V
DAC Code 1100
RED, GREEN, BLUE = 1V
DAC Code 1101
RED, GREEN, BLUE = 1V
DAC Code 1110
RED, GREEN, BLUE = 1V
DAC Code 1111
RED, GREEN, BLUE = 1V
Charge Pump (CPO)
1x Mode Output Impedance
1.5x Mode Output Impedance
V
BAT
= 3V, V
CPO
= 4.2V (Note 5)
2x Mode Output Impedance
V
BAT
= 3V, V
CPO
= 4.8V (Note 5)
CPO Voltage Regulation
1.5x Mode, I
CPO
= 2mA
2x Mode, I
CPO
= 2mA
CLOCK Frequency
SDA, SCL, ENRGBS, CAMHL
V
IL
, (Low Level Input Voltage)
V
IH
, (High Level Input Voltage)
V
OL
, Digital Output Low (SDA)
I
PULLUP
= 3mA
I
IH
SDA, SCL, ENRGBS, CAMHL = DV
CC
I
IL
SDA, SCL, ENRGBS, CAMHL = 0V
Serial Port Timing (Notes 6, 7)
t
SCL
Clock Operating Frequency
t
BUF
Bus Free Time Between Stop and Start Condition
t
HD,STA
Hold Time After (Repeated) Start Condition
●
●
●
●
●
●
0.6
1.2
0.3 • DV
CC
V
V
MHz
V
V
V
µA
µA
kHz
µs
µs
3208fa
0.7 • DV
CC
0.18
–1
–1
0.4
1
1
400
1.3
0.6
3
LTC3208
ELECTRICAL CHARACTERISTICS
PARAMETERS
t
SU,STA
t
SU,STO
t
HD,DAT(OUT)
t
HD,DAT(IN)
t
SU,DAT
t
LOW
t
HIGH
t
f
t
r
t
SP
CONDITIONS
Repeated Start Condition Setup Time
Stop Condition Setup Time
Data Hold Time
Input Data Hold Time
Data Setup Time
Clock Low Period
Clock High Period
Clock Data Fall Time
Clock Data Rise Time
Spike Suppression Time
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BAT
= 3.6V, DV
CC
= 3V, ENRGBS = Hi, R
REF
= 24k, C2 = C3 = 2.2µF,
C1 = C4 = 4.7µF, unless otherwise noted.
MIN
0.6
0.6
0
0
100
1.3
0.6
20
20
50
TYP
MAX
UNITS
µs
µs
ns
ns
ns
µs
µs
ns
ns
ns
900
300
300
Note 1:
Absolute Maximum Ratings are those values beyond which the
MTBF of a device may be impaired.
Note 2:
Based on long-term current density limitations. Assumes an
operating duty cycle of ≤10% under absolute maximum conditions for
durations less than 10 seconds. Max charge pump current for continuous
operation is 500mA.
Note 3:
Based on long-term current density limitations.
Note 4:
The LTC3208E is 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, characterization and
correlation with statistical process controls.
Note 5:
1.5x mode output impedance is defined as (1.5V
BAT
– V
CPO
)/I
OUT
.
2x mode output impedance is defined as (2V
BAT
– V
CPO
)/I
OUT
.
Note 6:
All values are referenced to V
IH
and V
IL
levels.
Note 7:
Guaranteed by Design.
TYPICAL PERFOR A CE CHARACTERISTICS
Mode Switch Dropout Times
5V
1x
1.5x
V
CPO
1V/DIV
2x
T
A
= 25°C
V
BAT
= 3.6V
250µs/DIV
3208 G01
4
U W
1.5x Mode CPO Ripple
T
A
= 25°C
V
BAT
= 3.6V
I
CPO
= 400mA
C
CPO
= 4.7µF
V
CPO
20mV/DIV
AC COUPLED
V
CPO
20mV/DIV
AC COUPLED
2x Mode CPO Ripple
T
A
= 25°C
V
BAT
= 3.6V
I
CPO
= 400mA
C
CPO
= 4.7µF
500ns/DIV
3208 G02
500ns/DIV
3208 G03
3208fa
LTC3208
TYPICAL PERFOR A CE CHARACTERISTICS
LED Pin Dropout Voltage
vs LED Pin Current
600
LED PIN DROPOUT VOLTAGE (mV)
500
SWITCH RESISTANCE (Ω)
0.40
V
BAT
= 3.6V
0.35
V
BAT
= 3.9V
0.30
400
300
200
100
0
10
20
30
40 50 60 70 80
LED CURRENT (mA)
90 100
3208 G04
V
BAT
= 3.6V
T
A
= 25°C
SWITCH RESISTANCE (Ω)
1.5x Mode CPO Voltage
vs Load Current
4.8
4.6
3.6V
CPO VOLTAGE (V)
4.4
3.2V
4.2
4.0
3.8 C2 = C3 = 2.2µF
C4 = 4.7µF
T
A
= 25°C
3.6
0
100
200
300
400
LOAD CURRENT (mA)
V
BAT
= 3V
3.3V
3.1V
3.4V
3.5V
SWITCH RESISTANCE (Ω)
2.8
2.4
2.2
2.0
1.8
1.6
–40
CPO VOLTAGE (V)
Oscillator Frequency
vs Supply Voltage
940
930
DV
CC
SHUTDOWN CURRENT (µA)
920
FREQUENCY (kHz)
910
900
890
880
870
860
850
840
2.7
3.0
4.2
3.3
3.6
3.9
V
BAT
SUPPLY VOLTAGE (V)
4.5
3208 G10
T
A
= –40°C
T
A
= 25°C
0.3
T
A
= 85°C
V
BAT
SHUTDOWN CURRENT (µA)
T
A
= 85°C
U W
1x Mode Switch Resistance vs
Temperature
0.45
I
CPO
= 200mA
V
BAT
= 3.3V
2.5
1.5x Mode Charge Pump Open-Loop
Output Resistance vs Temperature
(1.5V
BAT
– V
CPO
)/I
CPO
V
BAT
= 3V
V
CPO
= 4.2V
C2 = C3 = 2.2µF
2.3 C4 = 4.7µF
2.1
1.9
1.7
0.25
–40
–15
10
35
TEMPERATURE (°C)
60
85
3208 G05
1.5
–40
–15
10
35
TEMPERATURE (°C)
60
85
3208 G06
2x Mode Charge Pump Open-
Loop Output Resistance vs
Temperature (2V
BAT
– V
CPO
)/I
CPO
V
BAT
= 3V
V
CPO
= 4.8V
2.6 C2 = C3 = 2.2µF
C4 = 4.7µF
5.2
5.1
5.0
4.9
4.8
4.7
4.6
4.5
4.4
2x Mode CPO Voltage
vs Load Current
V
BAT
= 3V
V
BAT
= 3.1V
V
BAT
= 3.2V
V
BAT
= 3.3V
V
BAT
= 3.4V
V
BAT
= 3.5V
V
BAT
= 3.6V
500
3208 G07
–15
10
35
TEMPERATURE (°C)
60
85
3208 G08
C2 = C3 = 2.2µF
4.3 C4 = 4.7µF
T
A
= 25°C
4.2
0 100 200 300 400 500 600 700 800
LOAD CURRENT (mA)
3208 G09
DV
CC
Shutdown Current
vs DV
CC
Voltage
0.4
V
BAT
= 3.6V
T
A
= –40°C
8.5
7.5
6.5
5.5
4.5
3.5
2.5
V
BAT
Shutdown Current
vs V
BAT
Voltage
D
VCC
= 3V
T
A
= 85°C
0.2
T
A
= 25°C
0.1
T
A
= 25°C
T
A
= –40°C
0
2.7
3.0
3.3
3.6
3.9
DV
CC
VOLTAGE (V)
4.2
4.5
3208 G11
1.5
2.7
3.0
3.3
3.6
3.9
V
BAT
VOLTAGE (V)
4.2
4.5
3208 G12
3208fa
5
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