LTC3206
I
2
C Multidisplay
LED Controller
FEATURES
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■
■
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DESCRIPTIO
Step-Up/Direct-Connect Fractional Charge Pump
Provides Up to 92% Efficiency
Up to 400mA Continuous Output Current
Independent Current and Dimming Control for
1-6 LED MAIN, 1-4 LED SUB and RGB LED Displays
LED Currents Programmable Using 2-Wire I
2
C™
Serial Interface
1% LED Current Matching
Low Noise Constant Frequency Operation*
Minimal Component Count
Automatic Soft-Start Limits Inrush Current
16 Exponentially Spaced Dimming States Provides
128:1 Brightness Range for MAIN and SUB Displays
Up to 4096 Color Combinations for RGB Display
Low Operating Current: I
VIN
= 180µA
Tiny, Low Profile 24-Lead (4mm
×
4mm
×
0.75mm)
QFN Package
The LTC
®
3206 is a highly integrated multidisplay LED con-
troller. The part contains a high efficiency, low noise frac-
tional step-up/direct-connect charge pump to provide
power for both main and sub white LED displays plus an
RGB color LED display. The LTC3206 requires only four
small ceramic capacitors plus two resistors to form a
complete 3-display LED power supply and current
controller.
Maximum currents for the main/sub displays and RGB
display are set independently. Current for each LED is
controlled with an internal current source. Dimming and
ON/OFF control for all displays is achieved via a 2-wire
serial interface. Two auxiliary LED pins can be individually
assigned to either the MAIN or SUB displays. 16 individual
dimming states exist for both the MAIN and SUB displays.
Each of the RED, GREEN and BLUE LEDs have 16 dimming
states as well, resulting in up to 4096 color combinations.
The LTC3206 charge pump optimizes efficiency based on
V
IN
and LED forward voltage conditions. The part powers
up in direct-connect mode and automatically switches to
1.5x step-up mode once any enabled LED current source
begins to enter dropout. Internal circuitry prevents inrush
current and excess input noise during start-up and mode
switching. The LTC3206 is available in a 24-lead (4mm
×
4mm) QFN package.
APPLICATIO S
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Cellular Phones
Wireless PDAs
Multidisplay Handheld Devices
, LTC and LT are registered trademarks of Linear Technology Corporation.
I
2
C is a trademark of Philips Electronics N.V.
* U.S. Patent 6,411,531
TYPICAL APPLICATIO
2.2µF
2.2µF
V
IN
2.7V TO
4.5V
V
IN
2.2µF
LTC3206
MAIN1-4
AUX 1
SUB1-2
AUX 2
I
2
C SERIAL
INTERFACE
2
SERIAL PORT RGB
I
RGB
I
MS
3
2
4
CPO
MAIN DISPLAY
SUB DISPLAY
RGB ILLUMINATOR
EFFICIENCY (P
LED
/P
IN
) (%)
2.2µF
RED
GREEN BLUE
3206 TA01a
U
5-LED Main Display Efficiency
vs Input Voltage
100
90
80
70
60
50
40
30
20
10
FIVE LEDs AT 15mA/LED
(TYP V
F
AT 15mA = 3.2V)
T
A
= 25°C
3.3
3.6
3.9
INPUT VOLTAGE (V)
4.2
3206 TA01b
U
U
0
3.0
3206f
1
LTC3206
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
MAIN1
MAIN2
MAIN3
V
IN
, DV
CC
, CPO to GND............................... – 0.3V to 6V
SDA, SCL, ENRGB/S ................. – 0.3V to (DV
CC
+ 0.3V)
I
CPO
(Continuous) (Note 4) ................................ 400mA
(Pulsed at 10% Duty Cycle) (Note 4) ..................... 1A
I
MAIN1-4,
I
SUB1,2
, I
AUX 1, 2
(Note 4) ..................... 100mA
(Pulsed at 10% Duty Cycle) (Note 4) .............. 125mA
I
RED,GREEN,BLUE
(Note 4) ..................................... 100mA
(Pulsed at 10% Duty Cycle) (Note 4) .............. 125mA
I
MS
, I
RGB
(Note 4) .................................................. 1mA
CPO Short-Circuit Duration ............................ Indefinite
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 125°C
ORDER PART
NUMBER
18 BLUE
17 GREEN
16 RED
24 23 22 21 20 19
SUB1 1
SUB2 2
C2
–
3
C1
–
4
25
C1
+
5
C2
+
6
7
DV
CC
MAIN4
AUX2
AUX1
LTC3206EUF
15 V
IN
14 CPO
13 SGND
8
SDA
9 10 11 12
ENRGB/S
SCL
I
RGB
I
MS
UF PART
MARKING
3206
UF PACKAGE
24-LEAD (4mm
×
4mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 37°C/W,
θ
JC
= 2°C/W
EXPOSED PAD IS PGND (PIN 25)
MUST BE SOLDERED TO PCB
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
IN
= 3.6V, DV
CC
= 3V unless otherwise noted.
SYMBOL PARAMETER
Input Power Supply
V
IN
Operating Voltage
DV
CC
Operating Voltage
V
IN
Operating Current
DV
CC
Operating Current
V
IN
Shutdown Current
DV
CC
Shutdown Current
White LED Current (MAIN1-MAIN4, SUB1, SUB2, AUX1, AUX2)
I
MS
Servo Voltage
Full-Scale LED Current Ratio (I
LED
/I
MS
)
LED Dropout Voltage
LED Brightness Range
LED Current Matching
RGB LED Current (RED, GREEN, BLUE)
I
RGB
Servo Voltage
LED Current Ratio (I
LED
/I
RGB
)
RGB LED Dropout Voltage
RGB PWM (Duty Factor) Range
Charge Pump (CPO)
1x Mode Output Impedance
1.5x Mode Output Impedance
V
IN
= 3V, V
CPO
= 4.2V (Note 3)
0.68
1.90
Ω
Ω
25µA < I
RGB
< 75µA
RED, GREEN, BLUE Voltage = 1V
1.5x Mode Switch Threshold, I
LED
= 20mA
0/15
●
●
●
ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
2.7
1.5
TYP
MAX
4.5
5.5
UNITS
V
V
µA
mA
I
CPO
= I
MS
= I
RGB
= 0µA, Direct-Connect Mode
I
CPO
= I
MS
= I
RGB
= 0µA, 1.5x Step-Up Mode
Serial Port Idle
180
3.9
1
7.3
10
1
25µA < I
MS
< 75µA
MAIN1-MAIN4, SUB1, SUB2, AUX1, AUX2, Voltage = 1V
1.5x Mode Switch Threshold, I
LED
= 20mA
●
●
0.585
0.582
368
0.78
0.6
0.6
400
80
0.615
0.618
432
100
mA/mA
mV
%
%
MAIN-MAIN, MAIN-AUX, SUB-SUB, SUB-AUX
0.585
0.582
360
1
0.6
0.6
400
80
15/15
0.615
0.618
440
mA/mA
mV
%
2
U
µA
µA
µA
V
V
V
V
3206f
W
U
U
W W
W
LTC3206
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 3.6V, DV
CC
= 3V unless otherwise noted.
SYMBOL
PARAMETER
CPO Regulation Voltage
CLK Frequency
SDA, SCL, ENRGB/S
V
IL
V
IH
I
IH
I
IL
V
OL
t
SCL
t
BUF
t
HD, STA
t
SU, STA
t
SU, STD
t
HD, DAT(OUT)
t
HD, DAT(IN)
t
SU, DAT
t
LOW
t
HIGH
t
f
t
r
t
SP
Low Level Input Voltage
High Level Input Voltage
Input Current
Input Current
Digital Output Low (SDA)
Clock Operating Frequency
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
Input Data Hold Time
Data Setup Time
Clock Low Period
Clock High Period
Clock Data Fall Time
Clock Data RiseTime
Spike Suppression Time
1.3
0.6
0.6
0.6
225
0
100
1.3
0.6
20
20
50
with statistical process controls.
Note 3:
1.5x mode output impedance is defined as (1.5V
IN
– V
CPO
)/I
OUT
.
Note 4:
Based on long term current density limitations.
Note 5:
All values are referenced to V
IH
and V
IL
levels.
300
300
900
900
SDA, SCL, ENRGB/S = DV
CC
SDA, SCL, ENRGB/S = 0V
I
PULLUP
= 3mA
●
●
●
ELECTRICAL CHARACTERISTICS
CONDITIONS
I
CPO
= 20mA, 1.5x Mode
MIN
0.68
TYP
4.75
0.96
MAX
1.36
0.3 • DV
CC
UNITS
V
MHz
V
V
µA
µA
V
kHz
µs
µs
µs
µs
ns
ns
ns
µs
µs
ns
ns
ns
0.7 • DV
CC
–1
–1
1
1
0.4
400
Timing Characteristics (Note 5)
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
The LTC3206E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
TYPICAL PERFOR A CE CHARACTERISTICS
LED Pin Sink Current
vs LED Pin Voltage
100%
LED PIN DROPOUT VOLTAGE (mV)
CPO
AC COUPLED
(50mV/DIV)
I
LED
2.5mA/DIV
50%
V
IN
AC COUPLED
(50mV/DIV)
25%
0mA
200mV/DIV
V
LED
AT CURRENT SOURCE PIN
3206 G01
U W
Input and Output
Charge Pump Noise
500
LED Pin Dropout Voltage
vs LED Pin Current
V
IN
= 3.6V
T
A
= 25°C
400
300
200
I
CPO
= 200mA
500ns/DIV
V
IN
= 3.6V
C
IN
= C
CPO
= 1.6µF
3206 G02
100
0
10
20
30
40 50 60 70 80
LED CURRENT (mA)
90 100
3206 GO3
3206f
3
LTC3206
TYPICAL PERFOR A CE CHARACTERISTICS
1x Mode Switch Resistance
vs Temperature
0.9
I
CPO
= 100mA
SWITCH RESISTANCE (Ω)
0.8
V
IN
= 3.3V
V
IN
= 3.6V
0.7
V
IN
= 3.9V
OUTPUT RESISTANCE (Ω)
CPO VOLTAGE (V)
0.6
0.5
–40
–15
35
10
TEMPERATURE (°C)
Oscillator Frequency
vs Supply Voltage
1100
DV
CC
SHUTDOWN CURRENT (µA)
1000
FREQUENCY (kHz)
T
A
= 25°C
T
A
= –40°C
0.4
T
A
= 25°C
T
A
= –40°C
0.2
T
A
= 85°C
V
IN
SHUTDOWN CURRENT (µA)
900
T
A
= 85°C
800
700
2.7
3.0
4.2
3.3
3.6
3.9
V
IN
SUPPLY VOLTAGE (V)
4.5
3206 G07
1x Mode No Load Supply Current
vs Input Voltage
300
T
A
= 25°C
I
MS
= I
RGB
= 0µA
SUPPLY CURRENT (mA)
SUPPLY CURRENT (µA)
250
LED CURRENT (mA)
200
150
100
2.7
3.0
3.3
3.6
3.9
INPUT VOLTAGE (V)
4.2
4.5
3206 G10
4
U W
60
3206 G04
1.5x Mode Charge Pump Open-
Loop Output Resistance vs
Temperature (1.5V
IN
– V
CPO
)/I
CPO
2.50
V
IN
= 3V
V
CPO
= 4.2V
C
IN
= C
CPO
= C
FLY1
= C
FLY2
= 1.6µF
4.8
4.7
4.6
4.5
4.4
4.3
1.5x Mode CPO Voltage
vs Load Current
C
IN
= C
CPO
= C
FLY1
C
FLY2
= 1.6µF
T
A
= 25°C
3.6V
3.5V
3.4V
3.3V
3.2V
2.25
2.00
3.1V
4.2
4.1
4.0
3.9
V
IN
= 3V
1.75
85
1.50
–40
–15
10
35
TEMPERATURE (°C)
60
85
3206 G05
3.8
0
100
300
400
200
LOAD CURRENT (mA)
500
3206 G06
DV
CC
Shutdown Current
vs Input Voltage
0.5
V
IN
= 3.6V
8
10
V
IN
Shutdown Current
vs Input Voltage
DV
CC
= 3V
T
A
= 85°C
T
A
= 25°C
T
A
= –40°C
6
0.3
4
0.1
2
0
2.7
3.0
3.3
3.6
3.9
DV
CC
VOLTAGE (V)
4.2
4.5
3206 G08
0
2.7
3.0
3.3
3.6
3.9
INPUT VOLTAGE (V)
4.2
4.5
3206 G09
1.5x Mode Supply Current
vs I
CPO
(I
IN
– 1.5I
CPO
)
10
V
IN
= 3.6V
T
A
= 25°C
8
LED Pin Voltage for Higher LED
Currents
120
100
80
I
MS
, I
RGB
= 150µA
60
40
20
0
I
MS
, I
RGB
= 100µA
I
MS
, I
RGB
= 50µA
V
IN
= 3.6V
T
A
= 25°C
I
MS
, I
RGB
= 250µA
I
MS
, I
RGB
= 200µA
6
4
2
0
0
50
100
150
200
LOAD CURRENT (mA)
250
300
0
0.2
0.4
0.6
0.8
LED PIN VOLTAGE (V)
1.0
3206 G12
3206 G11
3206f
LTC3206
PI FU CTIO S
SUB1, SUB2 (Pins 1, 2):
Current Source Outputs for the
SUB Display White LEDs. The current for the SUB display
is controlled by the resistor on the I
MS
pin.The LEDs on the
SUB display can be set to exponentially increasing bright-
ness levels from 0.78% to 100% of full-scale. See Table 1.
C1
+
, C1
–
, C2
+
, C2
–
(Pins 5, 4, 6, 3):
Charge Pump Flying
Capacitor Pins. A 2.2µF X7R or X5R ceramic capacitor
should be connected from C1
+
to C1
–
and another from
C2
+
to C2
–
.
DV
CC
(Pin 7):
This pin sets the logic reference level of the
SDA, SCL and ENRGB/S pins.
SDA (Pin 8):
Input Data for the I
2
C Serial Port. Serial data
is shifted in one bit per clock to control the LTC3206 (see
Figures 3 and 4). The logic level for SDA is referenced to
DV
CC
.
SCL (Pin 9):
Clock Input for the I
2
C Serial Port (see Figures
3 and 4). The logic level for SCL is referenced to DV
CC
.
ENRGB/S (Pin 10):
This pin is used to enable and disable
either the RED, GREEN and BLUE current sources or the
SUB display depending on which is programmed to re-
spond via the I
2
C port. Once ENRGB/S is brought high, the
LTC3206 illuminates the RGB or SUB display with the
color combination or intensity that was previously pro-
grammed via the I
2
C port. The logic level for ENRGB/S is
referenced to DV
CC
.
I
MS
(Pin 11):
This pin controls the maximum amount of
LED current in both the MAIN and SUB LED displays. The
I
MS
pin servos to 0.6V when there is a resistor to ground.
The full scale (100%) currents in the MAIN and SUB
display LEDs will be 400 times the current at the I
MS
pin.
I
RGB
(Pin 12):
This pin controls the amount of LED current
at the RED, GREEN and BLUE LED pins. The I
RGB
pin
servos to 0.6V when there is a resistor to ground. The
current in the RED, GREEN and BLUE LEDs will be 400
times the current at the I
RGB
pin when programmed to full
scale.
SGND (Pin 13):
Ground for the control logic. This pin
should be connected directly to a low impedance ground
plane.
CPO (Pin 14):
Output of the Charge Pump. This output
should be used to power white, blue and “true” green
LEDs. Red LEDs can be powered from V
IN
or CPO. An X5R
or X7R low impedance (ceramic) 2.2µF charge storage
capacitor is required on CPO.
V
IN
(Pin 15):
Supply Voltage for the Charge Pump. The V
IN
pin should be connected directly to the battery and by-
passed with a 2.2µF X5R or X7R ceramic capacitor.
RED, GREEN, BLUE (Pins 16, 17, 18):
Current Source
Outputs for the RGB Illuminator LEDs. The currents for the
RGB LEDs are controlled by the resistor on the I
RGB
pin.
The RGB LEDs can independently be set to any duty cycle
from 0/15 through 15/15 under software control giving a
total of 16 shades per LED and 4096 colors for the
illuminator. See Table 1. The RGB LEDs are modulated at
1/240 the speed of the charge pump oscillator (approxi-
mately 4kHz).
MAIN1-MAIN4 (Pins 22, 21, 20, 19):
Current Source
Outputs for the Main Display White LEDs. The current for
the main display is controlled by the resistor on the I
MS
pin. The LEDs on the MAIN display can be set to 16
exponentially increasing brightness steps from 0.78% to
100% of full scale. See Table 1.
AUX1, AUX2 (Pins 23, 24):
Current source outputs for the
auxiliary white LEDs. The auxiliary current sources can be
individually assigned to be either MAIN display or SUB
display LEDs via the I
2
C serial port. When either AUX1 and/
or AUX2 are assigned to the MAIN display they will have
the same power setting as the other MAIN LEDs. Likewise,
when either AUX1 and/or AUX2 are assigned to the SUB
display they will have the same power setting as the other
SUB LEDs. The currents for the AUX1 and AUX2 pins are
controlled by the resistor on the I
MS
pin.
PGND (Pin 25, Exposed Pad):
Power Ground for the
Charge Pump. This pin should be connected directly to a
low impedance ground plane.
U
U
U
3206f
5
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