NOT RECOMMENDED FOR NEW DESIGN
SC618
Charge Pump Flash LED
Driver with Safety Timer
POWER MANAGEMENT
Features
Flash and spotlight — two selectable modes
Flash mode — up to 700mA output
Flash mode — 500mA max output (over rated voltage,
temperature, and load conditions)
Flash mode safety timer shut-off — 1 second
Spotlight mode set to 40% of flash current
Spotlight mode — up to 280mA output
Spotlight mode —1x mode (under most conditions)
for best efficiency
Input range — 3.0V to 5.25V
External flash control pin for synchronization to a cam-
era module or graphics controller
Short-circuit, over-voltage, and over-temperature pro-
tection
Soft-start functionality
Separate flash and spotlight control inputs for maxi-
mum versatility
Ultra-thin package MLPD-UT-10 — 3mm x 3mm x
0.6mm
Description
The SC618 is a high-current charge pump designed spe-
cifically for use with white LEDs used in camera flash
applications. 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
indefinitely 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 flash input overrides the control
input to make sure the flash function is activated .
The SC618 ultra-thin package provides both a low profile
and high thermal efficiency.
Applications
Mobile camera phones
Digital cameras
PDAs with built-in cameras
Typical Application Circuit
V
BAT
N
O
T
FO R
R EC
N O
EW M
M
D EN
ES D
IG ED
N
SC618
VIN
VOUT
GND
ISET
CTRL
FLASH
10μF
C1+
1μF
White LED
1μF
C1-
C2+
1μF
C2-
R
SET
FLASH
CTRL
February 6, 2008
1
NOT RECOMMENDED FOR NEW DESIGN
SC618
Pin Configuration
Ordering Information
Device
SC618ULTRT
(1)(2)
SC618EVB
Package
MLPD-UT-10 3×3
Evaluation Board
VIN
C2-
GND
C1-
FLASH
1
2
3
4
5
TOP VIEW
10
9
8
7
6
C2+
VOUT
C1+
CTRL
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.
MLPD-UT-10; 3x3, 10 LEAD
θ
JA
= 40°C/W
Marking Information
618
yyww
xxxx
yyww = Date code
xxxx = Semtech Lot Number
N
O
T
FO R
R EC
N O
EW M
M
D EN
ES D
IG ED
N
T
ISET
2
NOT RECOMMENDED FOR NEW DESIGN
SC618
Absolute Maximum Ratings
VIN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.5
VOUT (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.5
C1+, C2+ (V) . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (V
OUT
+ 0.3)
Pin Voltage - All Other Pins (V) . . . . . . -0.3 to (V
IN
+ 0.3)
Circuit Duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous
ESD Protection Level
(1)
(kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Recommended Operating Conditions
Ambient Temperature Range (°C) . . . . . . . . . . . . -40 to +85
Thermal Information
Thermal Resistance, Junction to Ambient
(2)
(°C/W) . . . . 40
Junction Temperature Range (°C) . . . . . . . . . . . . -40 to +150
Storage Temperature Range (°C) . . . . . . . . . . . . . -60 to +150
Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not recommended.
NOTES:
(1) Tested according to JEDEC standard JESD22-A114-B.
(2) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
Electrical Characteristics
Unless otherwise specified: T
A
= 25°C for TYP, -40°C to +60°C for MIN and MAX; C
BUCKET
= C
OUT
= 1.0μF (ESR < 0.1Ω); C
IN
= 10.0μF; V
IN
= 3.0V to 5.25V;
V
OUT
= 2.8V to 4.25V; R
SET
= 0.5Ω (0.1%).
Parameter
N
O
T
FO R
R EC
N O
EW M
M
D EN
ES D
IG ED
N
Symbol
Conditions
Min
Typ
700
Max
Units
FLASH high, R
SET
= 0.357Ω
3.7V < V
IN
< 4.2V, V
OUT
= 3.7V
(1)
FLASH high, R
SET
= 0.5Ω
3.3V < V
IN
< 4.2V
2.8V < V
OUT
< 4.25V
460
500
540
mA
Output Current
I
OUT
FLASH low, CTRL high, R
SET
= 0.357Ω
3.7V < V
IN
< 4.2V, V
OUT
= 3.4V
(1)
FLASH low, CTRL high, R
SET
= 0.5Ω
3.0V < V
IN
< 4.5V
2.8V < V
OUT
< 4.5V
FLASH high, R
SET
= 0.5Ω
3.3V < V
IN
< 4.2V
2.8V < V
OUT
< 4.25V
FLASH low, CTRL high, R
SET
= 0.5Ω
3.0V < V
IN
< 4.5V
2.8V < V
OUT
< 4.5V
FLASH high
280
170
200
230
230
250
270
mV
ISET Reference Voltage
V
ISET
85
100
115
3.4
2.0
0.1
5.0
4.5
2.0
mA
mA
μA
Quiescent Current
I
Q
FLASH low, CTRL high
FLASH low, CTRL low
3
NOT RECOMMENDED FOR NEW DESIGN
SC618
Electrical Characteristics (continued)
Parameter
Flash Mode Pulse Duration
(2)
Flash Mode Start-Up Time
(2)
Flash Mode Safety Timer
(2)
Spotlight Mode
Start-Up Time
(2,3)
Oscillator Frequency
Oscillator Frequency Accuracy
Short-Circuit Output
Current Limit
Symbol
t
FLASH
t
F-SU
t
SAFE
t
S-SU
f
OSC
Δf
OSC
I
SC
Conditions
3.3V < V
IN
< 4.2V
I
OUT
= 500mA, V
OUT
> 2.8V
t = 0 when FLASH goes high to
I
OUT
= 90% of final value
FLASH high
V
IN
= 4.2V, V
OUT
= 3.2V; t = 0 when CTRL goes high
to I
OUT
= 90% of final value
Device enabled
Min
Typ
Max
500
1
Units
ms
ms
s
ms
kHz
0.90
1.25
1
250
N
O
T
FO R
R EC
N O
EW M
M
D EN
ES D
IG ED
N
-15
15
600
2.1
%
mA
Steady State with VOUT shorted to GND
2x mode, 3.3V < V
IN
< 4.2V
Input Current Limit
I
LIMIT
A
1.38
150
°C
10
1.5
0.4
1
2
20
40
0.1
25
2x mode, V
IN
= 3.7V, V
OUT
= 3.7V, T
A
= 25°C
Rising threshold
Hysteresis
1.53
T
OT
Over-Temperature Protection
(2)
T
OT -HYS
V
IH
V
IL
Logic Input High Threshold
Logic Input Low Threshold
FLASH, CTRL
FLASH, CTRL
FLASH
CTRL
V
V
35
μA
70
2.0
μA
Logic Input High Current
I
IH
Logic Input Low Current
I
IL
FLASH, CTRL
Spotlight mode — I
OUT
= 200mA
FLASH mode — I
OUT
= 500mA
ISET Ripple Voltage
V
ISET(P-P)
100
mV
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.
4
NOT RECOMMENDED FOR NEW DESIGN
SC618
Typical Characteristics
Flash Current at 10ms, R
ISET
= 500mΩ, V
OUT
= 3.75V
515
Flash Current at 100ms, R
ISET
= 500mΩ, V
OUT
= 3.68V
515
510
510
LED Current (mA)
500
LED Current (mA)
505
505
500
495
495
490
490
485
3.3
3.45
N
O
T
FO R
R EC
N O
EW M
M
D EN
ES D
IG ED
N
485
3.3
3.6
3.6
3.75
3.9
4.05
4.2
3.45
VIN (V)
3.75
VIN (V)
3.9
4.05
4.2
Flash Current at 500ms, R
ISET
= 500mΩ, V
OUT
= 3.58V
515
Spotlight Current, R
ISET
= 500mΩ, V
OUT
= 3.16V
220
510
212
LED Current (mA)
LED Current (mA)
505
Transition to
2x Mode
1x Mode
204
500
196
495
490
485
3.3
188
3.45
3.6
3.75
3.9
4.05
4.2
180
5.25
4.8
4.35
VIN (V)
3.9
3.45
3
VIN (V)
Flash Duration, R
ISET
= 350mΩ, V
OUT
= 3.86V
(start), 3.61V (LED Heated 500ms)
755
Flash Duration, R
ISET
= 500mΩ, V
OUT
= 3.75V (start),
3.58V (LED Heated 500ms)
515
735
LED Current (mA)
509
LED Current (mA)
VIN=4.2V
VIN=3.7V
715
VIN=3.7V
503
VIN=4.2V
497
VIN=3.3V
695
VIN=3.4V
491
VIN=3.3V
675
0
100
200
300
Pulse Duration (ms)
400
500
485
0
100
200
300
Pulse Duration (ms)
400
500
5
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