LTC3210
MAIN/CAM LED Controller
in 3mm
×
3mm QFN
Description
The LTC
®
3210 is a low noise charge pump DC/DC converter
designed to drive four MAIN LEDs and one high current
CAM LED for camera lighting. The LTC3210 requires only
four small ceramic capacitors and two current set resis-
tors 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.
The full-scale current through the LEDs is programmed
via external resistors. ENM and ENC are toggled to adjust
the LED currents via internal counters and DACs. The
part is shut down when both ENM and ENC are low for
150µs (typ).
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 en-
ter dropout. The LTC3210 is 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 (8 Brightness Steps)
64:1 Brightness Control Range for MAIN Display
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
4-LED MAIN Display
Efficiency vs V
BAT
Voltage
100
90
EFFICIENCY (P
LED
/P
IN
) (%)
C1P
V
BAT
C1
2.2µF
V
BAT
C1M
C2P
C2M
CPO
C4
2.2µF
MLED1
MLED2
MLED3
MAIN
CAM
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)
LTC3210
ENM
ENC
ENM
ENC
RM
30.1k
1%
RC
24.3k
1%
MLED4
CLED
GND
3210 TA01
4.4
3210 TA01b
3210fb
LTC3210
absolute maximum ratings
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
.................................................................30mA
I
CLED
(Note 2)...................................................... 450mA
CPO Short-Circuit Duration .............................. Indefinite
Operating Temperature Range (Note 3) ...–40°C to 85°C
Storage Temperature Range .................. –65°C to 125°C
(Note 1)
pin conFiguration
TOP VIEW
V
BAT
C1M
C2M
12 GND
17
11 CLED
10 ENC
9 RC
5
MLED2
6
MLED3
7
MLED4
8
RM
C2P
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
orDer inFormation
LEAD FREE FINISH
LTC3210EUD#PBF
TAPE AND REEL
LTC3210EUD#TRPBF
PART MARKING
LBXH
PACKAGE DESCRIPTION
16-Lead (3mm
×
3mm) Plastic QFN
TEMPERATURE RANGE
–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/
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
V
BAT
Operating Voltage
I
VBAT
Operating Current
V
BAT
Shutdown Current
MLED1, MLED2, MLED3, MLED4 Current
LED Current Ratio (I
MLED
/I
RM
)
LED Dropout Voltage
LED Current Matching
MLED Current, 3-Bit Exponential DAC
I
MLED
= Full Scale
Mode Switch Threshold, I
MLED
= Full Scale
Any Two Outputs, I
MLED
= Full Scale
1 ENM Strobe (FS)
2 ENM Strobes
3 ENM Strobes
4 ENM Strobes
5 ENM Strobes
6 ENM Strobes
7 ENM Strobes (FS/64)
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electrical characteristics
CONDITIONS
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MIN
2.9
TYP
0.375
2.5
4.5
MAX
4.5
UNITS
V
mA
mA
mA
I
CPO
= 0, 1x Mode, MLED LSB Setting
I
CPO
= 0, 1.5x Mode
I
CPO
= 0, 2x Mode
ENM = ENC = LOW
l
3
463
515
100
1
20
10
5
2.5
1.25
0.625
0.312
6
567
µA
A/A
mV
%
mA
mA
mA
mA
mA
mA
mA
3210fb
LTC3210
electrical characteristics
PARAMETER
Unused MLED Detection
Test Current
Threshold Voltage
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.
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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
MLED Tied to CPO
V
CPO
– V
MLED
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)
l
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MIN
4
0.5
6750
TYP
MAX
16
1.5
UNITS
µA
V
A/A
mV
mA
mA
V
V
V
Ω
Ω
Ω
MHz
ms
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7500
500
380
54
V
BAT
4.55
5.05
0.5
3.15
3.95
0.8
0.4
8250
0.4
10
1.3
30
0.4
V
mA
V
V
µA
µA
ns
CPO = 0V, ENM = ENC = Low
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1.4
10
–1
60
50
50
1.16
150
150
1.20
250
250
1.24
70
15
20
1
ENM = ENC = 3.6V
ENM = ENC = 0V
Minimum Pulse Width
Low Time to Shutdown (ENC and ENM = Low)
Current Source Enable Time
(ENC or ENM = High) (Note 5)
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µs
µs
V
µA
Note 3:
The LTC3210E is 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.
3210fb
LTC3210
typical perFormance characteristics
Dropout Time from Shutdown
CPO
1V/DIV
EN
2V/DIV
2X
CPO
1V/DIV
ENC
2V/DIV
T
A
= 25°C unless otherwise stated.
Dropout Time When Enabled
2X
V
CPO
50mV/DIV
AC-COUPLED
1.5x CPO Ripple
V
BAT
= 3.6V
I
CPO
= 200mA
C
CPO
= 2.2µF
1X
MODE
RESET
1.5X
1.5X
1X
MODE
RESET
ENM = HIGH
500µs/DIV
3210 G01
250µs/DIV
3210 G02
500ns/DIV
3210 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
3210 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
3210 G06
V
BAT
= 3.3V
V
BAT
= 3.6V
V
BAT
= 3.9V
500ns/DIV
3210 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
OPEN LOOP OUTPUT RESISTANCE ( )
V
BAT
= 3.3V
V
BAT
= 3.4V
V
BAT
= 3.5V
V
BAT
= 3.6V
4.6
4.4
4.2
4.0
3.8
3.6
3.4
2x Mode Charge Pump Open-Loop
Output Resistance vs Temperature
(2V
BAT
– V
CPO
)/I
CPO
V
BAT
= 3V
V
CPO
= 4.8V
C2 = C3 = C4 = 2.2µF
CPO VOLTAGE (V)
5.2
5.1
5.0
4.9
4.8
4.7
4.6
4.5
4.4
4.3
–15
10
35
60
85
3210 G08
2x Mode CPO Voltage
vs Load Current
C2 = C3 = C4 = 2.2µF
V
BAT
= 3.6V
V
BAT
= 3.5V
V
BAT
= 3.4V
V
BAT
= 3.3V
V
BAT
= 3.2V
V
BAT
= 3.1V
V
BAT
= 3V
0
100
300
400
200
LOAD CURRENT (mA)
500
3210 G09
V
BAT
= 3.2V
V
BAT
= 3.1V
V
BAT
= 3V
0
100
200
300
400
LOAD CURRENT (mA)
500
3210 G07
3.2
–40
4.2
TEMPERATURE (°C)
3210fb
LTC3210
typical perFormance characteristics
500
CLED PIN DROPOUT VOLTAGE (mV)
T
A
= 25°C unless otherwise stated.
Oscillator Frequency
vs V
BAT
Voltage
T
A
= 25°C
CLED Pin Dropout Voltage
vs CLED Pin Current
V
BAT
= 3.6V
MLED PIN DROPOUT VOLTAGE (mV)
100
90
80
MLED Pin Dropout Voltage
vs MLED Pin Current
V
BAT
= 3.6V
850
840
830
FREQUENCY (kHz)
820
810
800
790
780
770
0
2
4
6 8 10 12 14 16 18 20
MLED PIN CURRENT (mA)
3210 G11
400
70
60
50
40
30
20
10
0
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
3210 G10
3.3
3.6
3.9
V
BAT
VOLTAGE (V)
4.2
4.5
3210 G12
5.0
V
BAT
SHUTDOWN CURRENT (µA)
4.5
4.0
3.5
3.0
2.5
2.0
V
BAT
Shutdown Current
vs V
BAT
Voltage
800
T
A
= 25°C
V
BAT
CURRENT (µA)
780
760
740
720
700
680
660
640
620
3.0
3.9
3.6
3.3
V
BAT
VOLTAGE (V)
4.2
4.5
3210 G13
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
15
T
A
= –40°C
10
T
A
= 85°C
5
1.5
2.7
600
2.7
3.0
3.6
3.9
3.3
V
BAT
VOLTAGE (V)
4.2
4.5
3210 G14
0
0
100
300
400
200
LOAD CURRENT (mA)
500
3210 G15
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
3210 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
3210 G17
3210fb
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