LTC3210-2/LTC3210-3
MAIN/CAM LED Controllers
with 32-Step Brightness Control
in 3mm
×
3mm QFN
DescripTion
The LTC
®
3210-2/LTC3210-3 are low noise charge pump
DC/DC converters designed to drive three or four MAIN
LEDs and one high current CAM LED for camera lighting.
The LTC3210-2/LTC3210-3 require only four small ceramic
capacitors and two current set resistors to form a complete
LED power supply and current controller.
Built-in soft-start circuitry prevents excessive inrush cur-
rent during start-up and mode changes. High switching
frequency enables the use of small external capacitors.
Independent MAIN and CAM full-scale current settings
are programmed by two external resistors.
Shutdown mode and current output levels are selected
via two logic inputs. ENM and ENC are toggled to adjust
the LED currents via internal counters and DACs. A 5-bit
linear DAC (32 steps) provides high resolution brightness
control for the MAIN display.
The charge pump optimizes efficiency based on the volt-
age 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 LTC3210-2/LTC3210-3 are available
in a 3mm × 3mm 16-lead QFN package.
FeaTures
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Low Noise Charge Pump Provides High Efficiency
with Automatic Mode Switching
Multimode Operation: 1x, 1.5x, 2x
Individual Full-Scale Current Set Resistors
Up to 500mA Total Output Current
Single Wire EN/Brightness Control for MAIN and
CAM LEDs
32:1 Linear Brightness Control Range for
MAIN Display
Three or Four 25mA Low Dropout MAIN LED Outputs
One 400mA Low Dropout CAM LED Output
Low Noise Constant Frequency Operation*
Low Shutdown Current: 3µA
Internal Soft-Start Limits Inrush Current During
Startup and Mode Switching
Open/Short LED Protection
No Inductors
3mm × 3mm 16-Lead Plastic QFN Package
applicaTions
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Multi-LED Light Supply for Cellphones/DSCs/PDAs
L, LT, LTC, LTM, Linear Technology and the Linear logo 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 applicaTion
C2
2.2µF
C3
2.2µF
100
C1P
V
BAT
C1
2.2µF
V
BAT
LTC3210-2
MLED1
MLED2
MLED3
ENM
ENC
ENM
ENC
RM
30.1k
1%
RC
24.3k
1%
MLED4
CLED
GND
321023 TA01
4-LED MAIN Display
Efficiency vs V
BAT
Voltage
MAIN
C4
2.2µF
CAM
EFFICIENCY (P
LED
/P
IN
) (%)
90
80
70
60
50
40
30
20 4 LEDs AT 9mA/LED
10 (TYP V
F
AT 9mA = 3V, NICHIA NSCW100)
T
A
= 25°C
0
3.0 3.2 3.4 3.6 3.8 4.0 4.2
V
BAT
(V)
C1M
C2P
C2M
CPO
4.4
321023 TA01b
321023fb
LTC3210-2/LTC3210-3
absoluTe MaxiMuM raTings
(Note 1)
V
BAT
, CPO to GND ........................................ –0.3V to 6V
ENM, ENC ...................................–0.3V to (V
BAT
+ 0.3V)
I
CPO
(Note 2) ....................................................... 600mA
I
MLED1-4
.................................................................35mA
I
CLED
(Note 2)...................................................... 500mA
CPO Short-Circuit Duration .............................. Indefinite
Operating Temperature Range (Note 3) ...–40°C to 85°C
Storage Temperature Range .................. –65°C to 125°C
pin conFiguraTion
TOP VIEW
V
BAT
C1M
C2M
C2P
TOP VIEW
V
BAT
C1M
C2M
12 GND
17
11 CLED
10 ENC
9 RC
5
MLED2
6
MLED3
7
NC
8
RM
C2P
12 GND
17
11 CLED
10 ENC
9 RC
5
MLED2
6
MLED3
7
MLED4
8
RM
C1P 1
CPO 2
ENM 3
MLED1 4
16 15 14 13
C1P 1
CPO 2
ENM 3
MLED1 4
16 15 14 13
UD PACKAGE
16-LEAD (3mm 3mm) PLASTIC QFN
T
JMAX
= 125°C, θ
JA
= 68°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
UD PACKAGE
16-LEAD (3mm 3mm) PLASTIC QFN
T
JMAX
= 125°C, θ
JA
= 68°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LTC3210EUD-2#PBF
LTC3210EUD-3#PBF
TAPE AND REEL
LTC3210EUD-2#TRPBF
LTC3210EUD-3#TRPBF
PART MARKING
LCHX
LCHY
PACKAGE DESCRIPTION
16-Lead (3mm × 3mm) Plastic QFN
16-Lead (3mm × 3mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
elecTrical characTerisTics
PARAMETER
V
BAT
Operating Voltage
I
VBAT
Operating Current
V
BAT
Shutdown Current
LED Current Ratio (I
MLED
/I
RM
)
LED Dropout Voltage
LED Current Matching
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.V
BAT
= 3.6V, C1 = C2 = C3 = C4 = 2.2µF RM = 30.1k, RC = 24.3k,
,
ENM = high, unless otherwise noted.
CONDITIONS
l
MIN
2.9
TYP
0.4
2.5
4.5
MAX
4.5
UNITS
V
mA
mA
mA
I
CPO
= 0, 1x Mode, LSB Setting
I
CPO
= 0, 1.5x Mode
I
CPO
= 0, 2x Mode
ENM = ENC = Low
I
MLED
= Full Scale
Mode Switch Threshold, I
MLED
= Full Scale
Any Two Outputs
l
3
481
525
75
0.5
6
589
µA
A/A
mV
%
321023fb
MLED1, MLED2, MLED3 and MLED4 (LTC3210-2 Only) Current
l
LTC3210-2/LTC3210-3
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.V
BAT
= 3.6V, C1 = C2 = C3 = C4 = 2.2µF RM = 30.1k, RC = 24.3k,
,
ENM = high, unless otherwise noted.
PARAMETER
MLED Current, 5-Bit Linear DAC
CLED Current
LED Current Ratio (I
CLED
/I
RC
)
LED Dropout Voltage
CLED Current, 3-Bit Linear DAC
Charge Pump (CPO)
1x Mode Output Voltage
1.5x Mode Output Voltage
2x Mode Output Voltage
1x Mode Output Impedance
1.5x Mode Output Impedance
2x Mode Output Impedance
CLOCK Frequency
Mode Switching Delay
CPO Short Circuit Detection
Threshold Voltage
Test Current
ENC, ENM
V
IL
V
IH
I
IH
I
IL
ENC, ENM Timing
t
PW
t
SD
t
EN
RM, RC
V
RM
, V
RC
I
RM
, I
RC
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: Based on long-term current density limitations. Assumes an
operating duty cycle of ≤10% under absolute maximum conditions
for durations less than 10 seconds. Maximum current for continuous
operation is 300mA.
l
l
l
l
l
elecTrical characTerisTics
CONDITIONS
1 ENM Strobe (FS)
31 ENM Strobes (FS/31)
I
CLED
= Full Scale
Mode Switch Threshold, I
CLED
= Full Scale
1 ENC Strobe (FS)
7 ENC Strobes (FS/7)
I
CPO
= 0mA
I
CPO
= 0mA
I
CPO
= 0mA
V
BAT
= 3.4V, V
CPO
= 4.6V (Note 4)
V
BAT
= 3.2V, V
CPO
= 5.1V (Note 4)
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MIN
TYP
20
0.640
MAX
UNITS
mA
mA
6930
7700
500
380
54
V
BAT
4.55
5.05
0.55
3.15
3.95
8470
A/A
mV
mA
mA
V
V
V
Ω
Ω
Ω
0.8
0.4
MHz
ms
0.4
10
1.3
30
0.4
V
mA
V
V
µA
µA
ns
CPO = 0V, ENM = ENC = Low
l
1.4
10
–1
200
50
50
1.16
150
150
1.20
250
250
1.24
80
15
20
1
ENM = ENC = 3.6V
ENM = ENC = 0V
Minimum Pulse Width
Low Time to Shutdown (ENC, ENM = Low)
Current Source Enable Time
(ENC, ENM = High) (Note 5)
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l
l
l
l
µs
µs
V
µA
Note 3: The LTC3210E-2/LTC3210E-3 are guaranteed to meet performance
specifications from 0°C to 85°C. Specifications over the –40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 4: 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 5: If the part has been shut down then the initial enable time is about
100µs longer due to the bandgap enable time.
321023fb
LTC3210-2/LTC3210-3
Typical perForMance characTerisTics
T
A
= 25°C unless otherwise stated.
Dropout Time from Shutdown
CPO
1V/DIV
EN
2V/DIV
5.1V
1X
2X
CPO
1V/DIV
ENC
2V/DIV
Dropout Time When Enabled
5.1V
1X
2X
V
CPO
50mV/DIV
AC-COUPLED
1.5x CPO Ripple
V
BAT
= 3.6V
I
CPO
= 200mA
C
CPO
= 2.2µF
1.5X
1.5X
MODE
RESET
MODE
RESET
ENM = HIGH
500µs/DIV
321023 G01
250µs/DIV
321023 G02
500ns/DIV
321023 G03
2x CPO Ripple
V
BAT
= 3.6V
I
CPO
= 200mA
C
CPO
= 2.2µF
SWITCH RESISTANCE ( )
V
CPO
20mV/DIV
AC-COUPLED
0.70
0.65
0.60
0.55
0.50
0.45
1x Mode Switch Resistance
vs Temperature
I
CPO
= 200mA
OPEN-LOOP OUTPUT RESISTANCE ( )
85
321023 G05
1.5x Mode Charge Pump Open-Loop
Output Resistance vs Temperature
(1.5V
BAT
– V
CPO
)/I
CPO
3.8
V
BAT
= 3V
V
CPO
= 4.2V
3.6
C2 = C3 = C4 = 2.2µF
3.4
3.2
3.0
2.8
2.6
2.4
–40
–15
10
35
60
85
321023 G06
V
BAT
= 3.3V
V
BAT
= 3.6V
V
BAT
= 3.9V
500ns/DIV
321023 G04
0.40
–40
–15
10
35
TEMPERATURE (°C)
60
TEMPERATURE (°C)
1.5x Mode CPO Voltage
vs Load Current
4.8
4.6
CPO VOLTAGE (V)
4.4
4.2
4.0
3.8
3.6
C2 = C3 = C4 = 2.2µF
V
BAT
= 3.3V
V
BAT
= 3.4V
V
BAT
= 3.5V
V
BAT
= 3.6V
OPEN-LOOP OUTPUT RESISTANCE ( )
4.6
2x Mode Charge Pump Open-Loop
Output Resistance vs Temperature
(2V
BAT
– V
CPO
)/I
CPO
V
BAT
= 3V
V
CPO
= 4.8V
4.4 C2 = C3 = C4 = 2.2µF
CPO VOLTAGE (V)
4.2
4.0
3.8
3.6
3.4
3.2
–40
–15
10
35
60
85
321023 G08
2x Mode CPO Voltage
vs Load Current
5.2
5.1
5.0
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
0
100
V
BAT
= 3.5V
V
BAT
= 3.4V
V
BAT
= 3.3V
V
BAT
= 3.2V
V
BAT
= 3.1V
V
BAT
= 3V
300
400
200
LOAD CURRENT (mA)
500
321023 G09
C2 = C3 = C4 = 2.2µF
V
BAT
= 3.6V
V
BAT
= 3.2V
V
BAT
= 3.1V
V
BAT
= 3V
0
100
200
300
400
LOAD CURRENT (mA)
500
321023 G07
TEMPERATURE (°C)
321023fb
LTC3210-2/LTC3210-3
Typical perForMance characTerisTics
T
A
= 25°C unless otherwise stated.
CLED Pin Dropout Voltage
vs CLED Pin Current
500
CLED PIN DROPOUT VOLTAGE (mV)
V
BAT
= 3.6V
MLED PIN DROPOUT VOLTAGE (mV)
120
100
FREQUENCY (kHz)
80
60
40
20
0
MLED Pin Dropout Voltage
vs MLED Pin Current
V
BAT
= 3.6V
850
840
830
820
810
800
790
780
770
0
2
4
6 8 10 12 14 16 18 20
MLED PIN CURRENT (mA)
321023 G11
Oscillator Frequency
vs V
BAT
Voltage
T
A
= 25°C
400
300
T
A
= 85°C
T
A
= –40°C
200
100
0
50
100
150 200 250 300 350
CLED PIN CURRENT (mA)
400
760
2.7
3.0
321023 G10
3.6
3.3
3.9
V
BAT
VOLTAGE (V)
4.2
4.5
321023 G12
5.0
V
BAT
SHUTDOWN CURRENT (µA)
4.5
V
BAT
Shutdown Current
vs V
BAT
Voltage
800
780
T
A
= 25°C
T
A
= –40°C
V
BAT
CURRENT (µA)
760
740
720
700
680
660
640
620
3.0
3.9
3.6
3.3
V
BAT
VOLTAGE (V)
4.2
4.5
600
1x Mode No Load V
BAT
Current
vs V
BAT
Voltage
RM = 33.2k
RC = 24.3k
SUPPLY CURRENT (mA)
20
1.5x Mode Supply Current
vs I
CPO
(IV
BAT
– 1.5I
CPO
)
V
BAT
= 3.6V
4.0
3.5
3.0
2.5
2.0
1.5
2.7
15
10
T
A
= 85°C
5
2.7
3.0
321023 G13
3.6
3.9
3.3
V
BAT
VOLTAGE (V)
4.2
4.5
0
0
100
300
400
200
LOAD CURRENT (mA)
500
321023 G15
321023 G14
2x Mode Supply Current
vs I
CPO
(IV
BAT
– 2I
CPO
)
20
V
BAT
= 3.6V
400
360
CLED PIN CURRENT (mA)
320
280
240
200
160
120
80
40
0
0
100
300
400
200
LOAD CURRENT (mA)
500
321023 G16
CLED Pin Current
vs CLED Pin Voltage
V
BAT
= 3.6V
SUPPLY CURRENT (mA)
15
10
5
0
0
0.2
0.6
0.8
0.4
CLED PIN VOLTAGE (V)
1
321023 G17
321023fb
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