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PDF SC605 Data sheet ( Hoja de datos )
| Número de pieza | SC605 | |
| Descripción | Charge Pump Flash LED Driver | |
| Fabricantes | Semtech | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de SC605 (archivo pdf) en la parte inferior de esta página. Total 12 Páginas | ||
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POWER MANAGEMENT
Description
The SC605 is a high-current charge pump designed spe-
cifically for use with white LEDs used in camera flash 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 SC605 has two modes of operation: Flash mode and
Spotlight mode. In Flash mode, the SC605 is capable of
delivering 500mA of regulated current for a duration of
500ms or up to 700mA for a reduced duration. In Spotlight
mode the SC605 can output 20%, 30%, or 40% of the Flash
mode current and 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 0.175mW, reducing the power dissipation require-
ment of the SC605. The Flash input (FLASH) overrides
the control inputs (CTRL0 and CTRL1) to ensure the Flash
function has the highest priority.
The thermally efficient MLPD-12 package and ceramic
bypass and bucket capacitors help make the SC605 a
high output current driver that requires a minimal amount
oTfyPpCicBaalreAap. plication Circuit
SC605
Charge Pump
Flwawswh.DaLtaESheDet4DU.croimver
Features
Two selectable modes - Flash and Spotlight
Up to 700mA output - Flash mode
Up to 280mA output - Spotlight mode
500mA output over specified temperature and volt-
age ranges - Flash mode
Spotlight mode selectable to 20%, 30%
and 40% of Flash current
3.0V to 5.25V input range
Flash control pin for synchronization to
a camera module or graphics controller
Short circuit, over-voltage and
over-temperature protection
Soft-start functionality
Three control inputs for maximum versatility
Shutdown current < 2μA
Micro-lead package MLPD-12, 3mm x 3mm
Applications
Mobile Camera Phones
Digital Cameras
PDAs with Built-in Cameras
Typical Application Circuit
VBAT
0µF
FLASH
CTRL0
CTRL
1 VIN
SC605
VOUT
11
3 GND
6 FLASH
8 CTRL0
9 CTRL1
5 NC
ISET 7
C1+ 10
C1- 4
C2+ 12
C2- 2
µF
µF
µF
white LED
0.5W
December 1, 2005
www.semtech.com
1 page  
SC605
POWER MANAGEMENT
www.DataSheet4U.com
Applications Information
General Operation
The SC605 is a powerful 2x charge pump designed to drive
a high-intensity white LED with a constant current (Spotlight
mode) or with a pulsed current of higher intensity (Flash
mode) used for camera flash.
In Flash mode the SC605 output can drive 500mA at 4.25V
into an LED for up to 500ms. The FLASH pin is used to
trigger Flash mode. In spotlight mode the SC605 regulates
the output current to the value selected by the CTRL0 and
CTRL1 inputs. Note that Flash mode has priority over
Spotlight mode, i.e., the FLASH pin triggers Flash mode
regardless of the state of the CTRL0 and CTRL1 pins.
Output current is regulated by attaching the ISET pin to the
cathode(s) of the LED package and a load sense resistor
(typically 0.5Ω). The ISET pin monitors the voltage at the
cathode and signals the charge pump to increase or de-
crease the output current until the ISET voltage reaches
the programmed setting. Programmed settings are shown
in Table 1:
Flash Mode
Flash mode is enabled whenever the FLASH pin is pulled
high and remains active until the FLASH pin is released.
While in Flash mode the reference voltage on the ISET pin
is set to 250mV. During Flash mode the charge pump de-
velops enough output current to drive an LED with 500mA
for a duration up to 500ms. The duration of the pulse is
limited by the amount of power that can be dissipated in
the SC605 before it exceeds the maximum operating tem-
perature. Note that if an output current less than the rated
500mA is desired the duration of the pulse can increase
proportionally. However, great care should be taken to in-
sure the FLASH pin is not held high for an extended amount
of time so that overheating does not occur. Extending flash
mode beyond the 500ms pulse limit could adversely affect
the long-term reliability of the SC605. Flash duration must
be derated at higher currents, for example, 700mA derates
to a maximum of 350ms. The plot below shows maximum
Flash mode current for extended duration times.
800
700
600
CTRL1
0
0
CTRL0
0
1
FLASH
0
0
VISET
0mV
50mV
Mode
Disabled
Spotlight
500
400
300
200
1
0
0
75mV
Spotlight
100
1
1
0
100mV
Spotlight
0
0
500
1000
1500
2000
Flash Duration [ms]
x
x 1 250mV
Table 1 - Control State Table
Flash
Maximum Flash Duration
The resistor value is chosen to set the current through the
LED based on this reference voltage. The resistor should
not be less than 0.35Ω due to the output current limitations
of the device. Note that the resistor sets both the Flash
mode current and the Spotlight mode current.
In
In
FSlpaosthligmhot dmeo, dIOeU,T
I=OUVT I=SETV/ISERTI/SETR=ISE2T.50mV
/
RISET.
Spotlight Mode
Spotlight mode is enabled by setting the CTRL0 and CTRL1
pins as shown in Table 1. When in Spotlight mode, the
SC605 can maintain a constant current indefinitely to drive
an LED or bank of LEDs. The ISET pin voltage is the refer-
eanndce10VI0SEmT aVn. dThheasse
three different settings - 50mV, 75mV,
settings allow the designer the flexibility
to select the output level needed to suit the application.
Protection Circuitry
The SC605 also provides protection circuitry that prevents
the device from operating in an unspecified state. These
include Input Over-Voltage Protection (IOVP), Output Over-
Voltage Protection (OVP), Over-Temperature Protection
(OTP), Over-Current Protection (OCP), and Short-Circuit
Current Protection (SCCP).
Input Over-Voltage Protection
Input over-voltage protection is included to prevent opera-
tion at high input voltages that could damage the device.
The IOVP circuit senses the input voltage and determines
when the supply exceeds 6V. When the voltage rises
above this threshold, the device is disabled until the input
voltage drops to a level within the specified input range.
Hysteresis is included in this circuit to avoid chattering
between states.
2005 Semtech Corp.
www.semtech.com
5 Page 
SC605
POWER MANAGEMENT
Outline Drawing - MLPD-12 Pin
www.DataSheet4U.com
AD
PIN 1
INDICATOR
(LASER MARK)
aaa C
LxN
E/2
D1
12
B
E
A1
A2
A
SEATING
PLANE
C
e/2
DIMENSIONS
DIM
INCHES
MIN NOM MAX
MILLIMETERS
MIN NOM MAX
A .031 - .039 0.80 - 1.00
A1 .000 - .002 0.00 - 0.05
A2 (.008)
(0.20)
b .006 .008 .010 0.15 0.20 0.25
D .114 .118 .122 2.90 3.00 3.10
D1 .074 .079 .083 1.87 2.02 2.12
E .114 .118 .122 2.90 3.00 3.10
E1 .042 .048 .052 1.06 1.21 1.31
e .018 BSC
0.45 BSC
L .012 .016 .020 0.30 0.40 0.50
N 12
12
aaa .003
0.08
bbb .004
0.10
E1
N
e
D/2
bxN
bbb C A B
NOTES:
1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS TERMINALS.
Marking Information
Top Marking
605
yyww
xxxxx
yyww = Datecode (Example: 0552)
xxxxx = Semtech lot number
2005 Semtech Corp.
11
www.semtech.com
11 Page | ||
| Páginas | Total 12 Páginas | |
| PDF Descargar | [ Datasheet SC605.PDF ] | |
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