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POWER MANAGEMENT
SC618
Charge Pump Flash LED
Driver with Safety Timer
Ultra-thin Package MLPD-UT-10 - only 0.6mm high!
(3mm x 3mm x 0.6mm)
Two selectable modes - Flash and Spotlight
Up to 700mA output - Flash Mode
500mA max output - Flash Mode (over rated voltage,
temperature, and load conditions)
1 second safety timer shut-off - Flash Mode
Spotlight Mode set to 40% of fl ash current
Up to 280mA output - Spotlight Mode
1x mode in Spotlight Mode under most conditions for
best efficiency (2x mode only when needed)
3.0V to 5.25V Input Range
External fl ash control pin for synchronization to a
camera module or graphics controller
Short-circuit, over-voltage, and over-temperature
protection
Soft-start functionality
Separate Flash and Spotlight control inputs for
maximum
versatility
January 20, 2006
Description
Features
Typical Application Circuit
The SC618 is a high-current charge pump designed spe-
cifi cally for use with white LEDs used in camera fl ash ap-
plications. Only two small bucket capacitors are required
to develop the output drive, providing a low EMI solution
compared to inductive boost regulators.
The SC618 has two modes of operation: Flash mode and
Spotlight mode. In Flash mode, the SC618 is capable of
delivering 500mA of regulated current for a duration of
500ms or up to 700mA for a reduced duration. A safety
timer is also included to ensure the LED cannot be left on
indefi nitely and overheat. In Spotlight mode the SC618
outputs 40% of the Flash mode current and can remain
enabled continuously.
An external resistor is connected in series with the LED to
set the current. In Flash mode, this resistor can dissipate
up to 175mW, reducing the power dissipation require-
ment of the SC618. The fl ash input (FLASH) overrides the
control input (CTRL) to make sure the fl ash function is ac-
tivated when called for.
The SC618 is packaged in the ultra-thin MLPD-UT-10
package - a low-profi le version of the thermally effi cient
MLPD-10 package - making ideal for use in applications
where component height is critical.
Mobile Camera Phones
Digital Cameras
PDAs with Built-in Cameras
Typical Application Circuit
Applications
Features
VBAT
SC618
VIN
1
C2-
2
C2+
10
C1-
4
C1+
8
VOUT
9
FLASH
5
CTRL
7
GND
3
ISET
6
1F
1F
FLASH
CTRL
1F
white LED
R
SET
10F
2
2006 Semtech Corp.
www.semtech.com
POWER MANAGEMENT
SC618
Absolute Maximum Ratings
Exceeding the specifi cations below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specifi ed in the
Electrical Characteristics section is not implied.
Unless otherwise specifi ed: T
A
= 25C for TYP, -40C to +60C for MIN and MAX; C
BUCKET
= C
OUT
= 1.0F (ESR < 0.1); C
IN
= 10.0F; V
IN
= 3.0V to 5.25V;
V
OUT
= 2.8V to 4.25V; R
SET
= 0.5 (0.1%).
Notes:
1) Calculated from package in still air, mounted to 3" x 4.5", 4 layer FR4 PCB with thermal vias under the exposed pad as per JESD51 standards.
2) Tested according to JEDEC standard JESD22-A114-B.
Parameter
Symbol
Maximum
Units
Input Supply Voltage
V
IN
-0.3 to +6.5
V
Output Voltage
V
OUT
-0.3 to +6.5
V
Pin Voltage - FLASH, CTRL, ISET, C1-, C2-
-0.3 to V
VIN
+ 0.3
V
Pin Voltage - C1+, C2+
-0.3 to V
VOUT
+ 0.3
V
Thermal Resistance, Junction to Ambient
(JESD51 Standard Method)
(1)
JA
49
C/W
VOUT Short-Circuit Duration
SC
Indefi nite
s
Operating Ambient Temperature Range
T
A
-40 to +85
C
Junction Temperature Range
T
J
-40 to +150
C
Storage Temperature Range
T
STG
-60 to +150
C
Peak IR Flow Temperature
T
LEAD
260
C
ESD Protection Level
(2)
V
ESD
2
kV
Parameter
Symbol
Conditions
Min
Typ
Max
Units
Output Current
I
OUT
FLASH high, R
SET
= 0.357
3.7V < V
IN
< 4.2V, V
OUT
= 3.7V
(1)
700
mA
FLASH high, R
SET
= 0.5
3.3V < V
IN
< 4.2V
2.8V < V
OUT
= 4.25V
460
500
540
FLASH low, CTRL high, R
SET
= 0.357
3.7V < V
IN
< 4.2V, V
OUT
= 3.4V
(1)
280
FLASH low, CTRL high, R
SET
= 0.5
3.0V < V
IN
< 4.5V
2.8V < V
OUT
< 4.5V
170
200
230
ISET Reference Voltage
V
ISET
FLASH high, R
SET
= 0.5
3.3V < V
IN
< 4.2V
2.8V < V
OUT
< 4.25V
230
250
270
mV
FLASH low, CTRL high, R
SET
= 0.5
3.0V < V
IN
< 4.5V
2.8V < V
OUT
< 4.5V
85
100
115
Absolute Maximum Ratings
Electrical Characteristics
3
2006 Semtech Corp.
www.semtech.com
POWER MANAGEMENT
SC618
Parameter
Symbol
Conditions
Min
Typ
Max
Units
Quiescent Current
I
Q
FLASH high
3.4
5.0
mA
FLASH low, CTRL high
2.0
4.5
mA
FLASH low, CTRL low
0.1
2.0
A
Flash Mode Pulse Duration
(2)
t
FLASH
3.3V < V
IN
< 4.2V
I
OUT
= 500mA, V
OUT
> 2.8V
500
ms
Flash Mode Start-Up Time
(2)
t
F-SU
t = 0 when FLASH goes high to
I
OUT
= 90% of fi nal value
1
ms
Flash Mode Safety Timer
(2)
t
SAFE
FLASH high
0.90
1.25
s
Spotlight Mode
Start-Up Time
(2,3)
t
S-SU
V
IN
= 4.2V, V
OUT
= 3.2V; t = 0 when CTRL
goes high to I
OUT
= 90% of fi nal value
1
ms
Oscillator Frequency
f
OSC
Device enabled
250
kHz
Oscillator Frequency Accuracy
f
OSC
-15
15
%
Short-Circuit Output
Current Limit
I
SC
Steady State with VOUT shorted to GND
600
mA
Input Current Limit
I
LIMIT
2x mode, 3.3V < V
IN
< 4.2V
1.0
2.1
A
2x mode, V
IN
= 3.7V, V
OUT
= 3.7V, T
A
= 25C
1.38
1.53
Over-Temperature Protection
(2)
T
OT
150
C
T
OT -HYS
Hysteresis
10
Logic Input High Threshold
V
IH
FLASH, CTRL
1.5
V
Logic Input Low Threshold
V
IL
FLASH, CTRL
0.4
V
Logic Input High Current
I
IH
FLASH
1
20
35
A
CTRL
2
40
70
Logic Input Low Current
I
IL
FLASH, CTRL
0.1
2.0
A
Notes:
1) V
OUT
required by the typical LED at this current.
2) Guaranteed by design - not tested in production.
3) If conditions force 2x mode operation, this start-up time will increase by approximately 32ms due to the timer that is enabled to ensure 2x mode is needed.
Electrical Characteristics (Cont.)
4
2006 Semtech Corp.
www.semtech.com
POWER MANAGEMENT
SC618
DEVICE
PACKAGE
(1)
SC618ULTRT
(2)(1)
(1,2)
MLPD-UT-10 3x3
SC618EVB
Evaluation Board
Notes:
1) Available in tape and reel only. A reel contains 3,000 devices.
2) Lead-free package only. Device is WEEE and RoHS compliant.
Pin Confi guration
Ordering Information
TOP VIEW
1
2
3
4
10
9
8
7
5
6
MLP10: 3X3 10 LEAD
T
VIN
C2-
GND
C1-
FLASH
C2+
VOUT
C1+
CTRL
ISET
Marking Information
618
yyww
xxxx
Top Mark
yyww = Datecode (Example = 0552)
xxxx = Semtech Lot Number
5
2006 Semtech Corp.
www.semtech.com
POWER MANAGEMENT
SC618
Pin#
Pin Name Pin Function
1
VIN
Input voltage.
2
C2-
Negative terminal of bucket capacitor 2.
3
GND
Ground - connect to ground plane using multiple vias.
4
C1-
Negative terminal of bucket capacitor 1.
5
FLASH
Flash mode enable pin - puts the device in active Flash mode when high and also overrides
CTRL.
6
ISET
Current-setting reference pin - connect to the LED cathode and the current setting resistor.
7
CTRL
Control input bit - used to enable and set the output current in Spotlight mode when high.
8
C1+
Positive terminal of bucket capacitor 1.
9
VOUT
Output pin - connect to the LED anode.
10
C2+
Positive terminal of bucket capacitor 2.
T
Thermal
Pad
Pad for heat sinking purposes - not connected internally. Connect to ground plane using
multiple vias.
Pin Descriptions
Block Diagram
CHARGE
PUMP
250kHz
Logic Control
and Flash Mode
Timer
Reference
Voltage
Generator
LDO
C1+
C1-
C2+
C2-
VOUT
ISET
VIN
CTRL
FLASH
GND
8
4
10
2
9
3
6
5
7
1
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