LTC3210-1
MAIN/CAM LED Controller
with 64-Step Brightness Control
in 3mm
×
3mm QFN
DESCRIPTION
The LTC
®
3210-1 is a low noise charge pump DC/DC con-
verter designed to drive four MAIN LEDs and one high
current CAM LED for camera lighting. The LTC3210-1
requires only four small ceramic capacitors and two cur-
rent 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 6-bit
linear DAC (64 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 LTC3210-1 is available in a 3mm
×
3mm
16-lead QFN package. Standard (0.75mm) and ultra-thin
(0.55mm) package profiles are available.
FEATURES
■
■
■
■
■
■
■
■
■
■
■
■
■
■
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
64:1 Linear 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 Packages with
0.55mm and 0.75mm Profiles
APPLICATIONS
■
Multi-LED Light Supply for Cellphones/DSCs/PDAs
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by US Patents including 6411531.
TYPICAL APPLICATION
C2
2.2μF
C3
2.2μF
100
90
4-LED MAIN Display
Efficiency vs V
BAT
Voltage
C1P
V
BAT
C1
2.2μF
V
BAT
C1M
C2P
C2M
CPO
C4
2.2μF
MLED1
MLED2
MLED3
MAIN
CAM
EFFICIENCY (P
LED
/P
IN
) (%)
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)
LTC3210-1
ENM
ENC
ENM
ENC
RM
30.1k
1%
RC
24.3k
1%
MLED4
CLED
GND
32101 TA01
4.4
32101 TA01b
32101fc
1
LTC3210-1
ABSOLUTE
(Note 1)
AXI U RATI GS
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
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
PIN CONFIGURATION
TOP VIEW
V
BAT
C1M
C2M
C2P
TOP VIEW
V
BAT
C1M
C2M
12 GND
17
11 CLED
10 ENC
9
5
MLED2
6
MLED3
7
MLED4
8
RM
RC
C2P
12 GND
17
11 CLED
10 ENC
9
5
MLED2
6
MLED3
7
MLED4
8
RM
RC
C1P 1
CP0 2
ENM 3
MLED1 4
16 15 14 13
16 15 14 13
C1P 1
CPO 2
ENM 3
MLED1 4
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-1#PBF
LTC3210EPD-1#PBF
TAPE AND REEL
LTC3210EUD-1#TRPBF
LTC3210EPD-1#TRPBF
PART MARKING
LCBT
LCXT
PACKAGE DESCRIPTION
16-Lead (3mm
×
3mm) Plastic QFN
16-Lead (3mm
×
3mm) Plastic UTQFN
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/
The
●
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
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
●
ELECTRICAL CHARACTERISTICS
CONDITIONS
●
V
BAT
Shutdown Current
MLED1, MLED2, MLED3, MLED4 Current
LED Current Ratio (I
MLED
/I
RM
)
LED Dropout Voltage
LED Current Matching
2
U
W W
W
PD PACKAGE
16-LEAD (3mm 3mm) PLASTIC UTQFN
T
JMAX
= 150°C,
θ
JA
= 68°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO A 4-LAYER PCB
MIN
2.9
TYP
0.4
2.5
4.5
3
MAX
4.5
UNITS
V
mA
mA
mA
6
589
μA
A/A
mV
%
32101fc
●
481
535
75
0.5
LTC3210-1
ELECTRICAL CHARACTERISTICS
PARAMETER
MLED Current, 6-Bit Linear DAC
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.
●
●
●
●
●
The
●
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
1 ENM Strobe (FS)
63 ENM Strobes (FS/63)
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)
●
●
MIN
TYP
20
0.318
MAX
UNITS
mA
mA
4
0.5
6930
7700
500
380
54
V
BAT
4.55
5.05
0.55
3.15
3.95
0.8
0.4
0.4
10
16
1.5
8470
μA
V
A/A
mV
mA
mA
V
V
V
Ω
Ω
Ω
MHz
ms
●
1.3
30
0.4
V
mA
V
V
μA
μA
ns
CPO = 0V, ENM = ENC = Low
●
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)
●
●
●
●
●
μs
μs
V
μA
Note 3:
The LTC3210-1 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 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.
32101fc
3
LTC3210-1
TYPICAL PERFORMANCE CHARACTERISTICS
Dropout Time from Shutdown
CPO
1V/DIV
EN
2V/DIV
5.1V
1.5X
1X
2X
CPO
1V/DIV
ENC
2V/DIV
T
A
= 25°C unless otherwise stated.
Dropout Time When Enabled
5.1V
1.5X
1X
V
CPO
50mV/DIV
AC
COUPLED
2X
1.5x CPO Ripple
V
BAT
= 3.6V
I
CPO
= 200mA
C
CPO
= 2.2μF
MODE
RESET
MODE
RESET
ENM = HIGH
500μs/DIV
32101 G01
250μs/DIV
32101 G02
500ns/DIV
32101 G03
2x CPO Ripple
V
BAT
= 3.6V
I
CPO
= 200mA
C
CPO
= 2.2μF
SWITCH RESISTANCE (Ω)
V
CPO
20mV/DIV
AC
COUPLED
0.70
0.65
0.60
1x Mode Switch Resistance
vs Temperature
I
CPO
= 200mA
OPEN LOOP OUTPUT RESISTANCE (Ω)
3.8
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
3.6
C2 = C3 = C4 = 2.2μF
3.4
3.2
3.0
2.8
2.6
2.4
–40
V
BAT
= 3.3V
0.55
0.50
0.45
V
BAT
= 3.6V
V
BAT
= 3.9V
500ns/DIV
32101 G04
0.40
–40
–15
10
35
TEMPERATURE (°C)
60
85
32101 G05
–15
10
35
60
85
32101 G06
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
0
100
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 (Ω)
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
5.2
5.1
5.0
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
–15
10
35
60
85
32101 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
32101 G09
V
BAT
= 3.2V
V
BAT
= 3.1V
V
BAT
= 3V
200
300
400
LOAD CURRENT (mA)
500
32101 G07
TEMPERATURE (˚C)
32101fc
4
LTC3210-1
TYPICAL PERFORMANCE CHARACTERISTICS
CLED Pin Dropout Voltage
vs CLED Pin Current
500
CLED PIN DROPOUT VOLTAGE (mV)
V
BAT
= 3.6V
MLED PIN DROPOUT VOLTAGE (mV)
120
V
BAT
= 3.6V
100
830
FREQUENCY (kHz)
80
60
40
20
770
0
0
2
4
6 8 10 12 14 16 18 20
MLED PIN CURRENT (mA)
32101 G11
T
A
= 25°C unless otherwise stated.
Oscillator Frequency
vs V
BAT
Voltage
850
840
T
A
= 25°C
MLED Pin Dropout Voltage
vs MLED Pin Current
400
820
810
800
790
780
T
A
= 85°C
T
A
= –40°C
300
200
100
0
50
100
150 200 250 300 350
CLED PIN CURRENT (mA)
400
760
2.7
3.0
3.3
3.6
3.9
V
BAT
VOLTAGE (V)
4.2
4.5
32101 G10
32101 G12
V
BAT
Shutdown Current
vs V
BAT
Voltage
5.0
V
BAT
SHUTDOWN CURRENT (μA)
4.5
4.0
3.5
3.0
2.5
2.0
1.5
2.7
T
A
= –40°C
T
A
= 25°C
V
BAT
CURRENT (μA)
800
780
760
740
720
700
680
660
640
620
600
3.0
3.9
3.6
3.3
V
BAT
VOLTAGE (V)
4.2
4.5
1x Mode No Load V
BAT
Current
vs V
BAT
Voltage
20
RM = 33.2k
RC = 24.3k
SUPPLY CURRENT (mA)
15
1.5x Mode Supply Current
vs I
CPO
(IV
BAT
– 1.5I
CPO
)
V
BAT
= 3.6V
10
T
A
= 85°C
5
0
2.7
3.0
3.6
3.9
3.3
V
BAT
VOLTAGE (V)
4.2
4.5
0
100
300
400
200
LOAD CURRENT (mA)
500
32101 G15
32101 G13
32101 G14
2x Mode Supply Current
vs I
CPO
(IV
BAT
– 2I
CPO
)
20
V
BAT
= 3.6V
400
360
CLED PIN CURRENT (mA)
SUPPLY CURRENT (mA)
15
320
280
240
200
160
120
80
40
0
0
100
300
400
200
LOAD CURRENT (mA)
500
32101 G16
CLED Pin Current
vs CLED Pin Voltage
V
BAT
= 3.6V
10
5
0
0
0.2
0.6
0.8
0.4
CLED PIN VOLTAGE (V)
1
32101 G17
32101fc
5
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