Charge Pump Flash Driver with Safety Timer POWER MANAGEMENT Featu
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SC619
Charge Pump Flash Driver with Safety Timer
POWER MANAGEMENT Features
Flash spotlight selectable modes Flash mode 700mA output Flash mode 500mA output (over rated voltage, temperature, load conditions) Flash mode safety timer shut-off second Spotlight mode flash current Spotlight mode 140mA output Spotlight mode mode (under most conditions) best efficiency Input range 3.0V 5.25V External flash control synchronization camera module graphics controller Short-circuit, over-voltage, over-temperature protection Soft-start functionality Separate flash spotlight control inputs maximum versatility Ultra-thin package MLPD-UT-10 0.6mm
Description
SC619 high-current charge pump designed specifically with white LEDs used camera flash applications. Only small bucket capacitors required develop output drive, providing solution compared inductive boost regulators. SC619 modes operation: flash mode spotlight mode. flash mode, SC619 capable delivering 500mA regulated current duration 500ms 700mA reduced duration. safety timer also included ensure cannot left indefinitely overheat. spotlight mode SC619 outputs flash mode current remain enabled continuously. external resistor connected series with current. flash mode, this resistor dissipate 175mW, reducing power dissipation requirement SC619. flash input overrides control input make sure flash function activated SC619 ultra-thin package provides both profile high thermal efficiency.
Applications
Mobile camera phones Digital cameras PDAs with built-in cameras
Typical Application Circuit
SC619
VBAT VOUT ISET CTRL FLASH
White
C1C2+
RSET
FLASH CTRL
August 2007
SC619
Configuration Ordering Information
Device
SC619ULTRT(1)(2) SC619EVB
C2GND C1FLASH
Package
MLPD-UT-10 Evaluation Board
VIEW
VOUT CTRL ISET
Notes: Available tape reel only. reel contains 3,000 devices. Lead-free package only. Device WEEE RoHS compliant.
MLPD-UT-10; 3x3, LEAD 49°C/W
Marking Information
yyww xxxx
yyww Date code xxxx Semtech Number
SC619
Absolute Maximum Ratings
-0.3 +6.5 VOUT -0.3 +6.5 C1+, -0.3 (VOUT 0.3) Voltage Other Pins -0.3 (VIN 0.3) Circuit Duration Continuous Protection Level(1) (kV) Thermal Resistance, Junction Ambient(2) (°C/W) Junction Temperature Range (°C) +150 Storage Temperature Range (°C) +150 Peak Reflow Temperature (10s 30s) (°C) +260
Recommended Operating Conditions
Ambient Temperature Range (°C)
Thermal Information
Exceeding above specifications result permanent damage device device malfunction. Operation outside parameters specified Electrical Characteristics section recommended. NOTES: Tested according JEDEC standard JESD22-A114-B. Calculated from package still air, mounted 4.5", layer with thermal vias under exposed JESD51 standards.
Electrical Characteristics
Unless otherwise specified: 25°C TYP, -40°C +60°C MAX; CBUCKET COUT 1.0F (ESR 0.1); 10.0F; 3.0V 5.25V; VOUT 2.8V 4.25V; RSET (0.1%).
Parameter
Symbol
Conditions
FLASH high, RSET 0.357 3.7V 4.2V, VOUT 3.7V(1) FLASH high, RSET 3.3V 4.2V 2.8V VOUT 4.25V FLASH low, CTRL high, RSET 0.357 3.7V 4.2V, VOUT 3.4V(1) FLASH low, CTRL high, RSET 3.0V 4.5V 2.8V VOUT 4.5V FLASH high, RSET 3.3V 4.2V 2.8V VOUT 4.25V FLASH low, CTRL high, RSET 3.0V 4.5V 2.8V VOUT 4.5V FLASH high
Units
Output Current
IOUT
ISET Reference Voltage
VISET
37.5
62.5
Quiescent Current
FLASH low, CTRL high FLASH low, CTRL
SC619
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
tFLASH tF-SU tSAFE tS-SU fOSC fOSC
Conditions
3.3V 4.2V IOUT 500mA, VOUT 2.8V when FLASH goes high IOUT final value FLASH high 4.2V, VOUT 3.2V; when CTRL goes high IOUT final value Device enabled
Units
0.90
1.25
Steady State with VOUT shorted mode, 3.3V 4.2V 1.38 1.53
Input Current Limit
ILIMIT mode, 3.7V, VOUT 3.7V, 25°C Rising threshold Hysteresis FLASH, CTRL FLASH, CTRL FLASH
Over-Temperature Protection(2) -HYS Logic Input High Threshold Logic Input Threshold
Logic Input High Current
CTRL
Logic Input Current
FLASH, CTRL Spotlight mode IOUT 100mA
ISET Ripple Voltage
VISET(P-P) FLASH mode IOUT 500mA
Notes: VOUT required typical this current. Guaranteed design tested production. conditions force mode operation, this start-up time will increase approximately 32ms timer that enabled ensure mode needed.
SC619
Typical Characteristics
Flash Current 10ms, RISET 500m, VOUT 3.75V
Flash Current 100ms, RISET 500m, VOUT 3.68V
Current (mA)
Current (mA)
3.45 3.75 4.05
3.45
3.75
4.05
Flash Current 500ms, RISET 500m, VOUT 3.58V
Spotlight Current, RISET 500m, VOUT 2.93V
120.0
112.0
Current (mA)
3.75
Current (mA)
104.0
96.0
88.0
3.45
4.05
80.0 3.00
3.45
3.90
4.35
4.80
5.25
Flash Duration, RISET 350m, VOUT 3.86V (start), 3.61V (LED Heated 500ms)
Flash Duration, RISET 500m, VOUT 3.75V (start), 3.58V (LED Heated 500ms)
Current (mA)
Current (mA)
VIN=4.2V VIN=3.7V
VIN=3.7V
VIN=4.2V
VIN=3.3V
VIN=3.4V
VIN=3.3V Pulse Duration (ms)
Pulse Duration (ms)
SC619
Typical Characteristics (continued)
Flash Mode Ripple, RISET 500m Start-Up Flash Mode, 500mA
100mV/DIV 200mV/DIV 200mV/DIV Time (4s/div) Time (40s/div)
100mV/DIV 2V/DIV 2V/DIV
Safety Timer Shut-Off
Spotlight Mode Ripple, RISET 500m
Ch1: 100mV/DIV Ch2: 2V/DIV Ch3: 5V/DIV Time (200ms/div) Time (4s/div)
Ch1: 50mV/DIV Ch2: 50mV/DIV Ch3: 50mV/DIV
Spotlight Mode Ripple, RISET 500m
Short Circuit Current Limiting, 5.25V, VOUT
Ch1: mV/DIV Ch2: mV/DIV Ch3: mV/DIV Time (4s/div) Time (400ms/div) Ch1: 2V/DIV Ch4: 100mA/DIV
SC619
Descriptions
Pin#
Name
C2GND C1FLASH ISET CTRL VOUT Thermal
Function
Input voltage Negative terminal bucket capacitor Ground- connect ground plane using multiple vias Negative terminal bucket capacitor Flash mode enable pin- puts device active flash mode when high also overrides CTRL. Current-setting reference connect cathode current setting resistor. Control input used enable output current spotlight mode when high. Positive terminal bucket capacitor Output connect anode Positive terminal bucket capacitor heat sinking purposes connected internally. Connect ground plane using multiple vias.
SC619
Block Diagram
250kHz
CTRL FLASH Logic Control Flash Mode Timer
CHARGE PUMP
Reference Voltage Generator
VOUT
ISET
SC619
Applications Information
General Operation
SC619 powerful dual-mode charge pump designed drive high-intensity white LED. constant current spotlight mode pulsed current with higher intensity used camera flash. device operates mode while operating flash mode. spotlight mode operate either mode depending load current, load voltage, input voltage levels. flash mode SC619 output drive 500mA 4.25V into minimum duration 500ms under temperature input conditions. FLASH used trigger this mode (active high). spotlight mode SC619 regulates output current flash mode current setting, when CTRL pulled high FLASH low. Flash mode priority over spotlight mode, i.e., FLASH triggers flash mode regardless state CTRL pin. Output current regulated attaching ISET cathode(s) package resistance sense resistor (typically 0.5). ISET monitors voltage cathode signals charge pump increase decrease output current until ISET voltage reaches programmed setting. resistor value chosen current through based this reference voltage. resistor chosen either flash mode current spotlight mode current, should less than 0.35 output current limitations device. example, 700mA derates maximum 350ms. flash mode, IOUT 250mV/RISET. Figure shows maximum flash mode current extended duration times.
Flash Current [mA]
1000
Flash Duration [ms]
Figure Maximum Flash Duration
Flash Mode Safety Timer
SC619 provides time-out protection function when flash mode. output disabled FLASH held high longer than second protect LED. Once this time-out occurred, output will stay disabled until FLASH been pulled then re-enabled.
Spotlight Mode
Spotlight mode enabled setting CTRL high keeping FLASH low. When spotlight mode, SC619 maintain constant current indefinitely drive bank LEDs. ISET reference voltage 50mV that output current maintained 100mA when resistor used. Spotlight current always flash current given value RISET. spotlight mode, IOUT 50mV/RISET. maximize power efficiency, SC619 been designed operate mode when conditions require charge pump active. When first enabled SC619 attempts regulate voltage ISET mode. voltage ISET cannot maintained this condition persists longer than 32ms, then charge pump will change mode operation. typical application, SC619 will operate mode until supply voltage decreases sufficiently
Flash Mode
Flash mode enabled whenever FLASH pulled high remains active until FLASH released. This mode higher priority than spotlight mode, state CTRL overridden whenever FLASH activated. While flash mode reference voltage ISET 250mV. duration pulse limited amount power that dissipated SC619 before exceeds maximum operating temperature. output current less than rated 500mA desired, duration pulse increase proportionally. Extending flash mode beyond 500ms pulse limit could adversely affect long term reliability SC619. Flash duration must derated higher currents.
SC619
Applications Information (continued)
that voltage ISET longer maintained. After 32ms delay (included prevent false transitions) charge pump will convert mode. After charge pump switches from mode mode, device remains mode until part turned off. part re-enabled spotlight mode, will begin operation mode determine appropriate mode operation previously described. Over-Current Protection When SC619 mode, input current will approximately double required output. When steady-state load requires maximum current available mode, circuit prevents device from overheating from excessive power dissipation. This feature protects device when mode. current limit lower mode lower current requirements. Short-Circuit Current Protection SSCP provided limit current that sourced when output shorted ground. When short circuit forces VOUT drop below SCCP detects condition limits output current.
Protection Circuitry
SC619 provides several protection features safeguard device from catastrophic failures. These features include:
Input Over-Voltage Protection (IOVP) Output Over-Voltage Protection (OVP) Over-Temperature Protection (OTP) Over-Current Protection (OCP) Short-Circuit Current Protection (SCCP)
Resistor Selection
ISET resistor selection critical generating correct current. value chosen spotlight mode current flash mode current, current settings dependent same resistor. recommended that resistor selected match desired current flash mode. This allows designer SC619's maximum current select resistor package size necessary power dissipation required flash mode. typical application uses resistor flash mode current 500mA spotlight mode current 100mA. high precision resistor should used ensure specified accuracy current. avoid malfunction charge pump, recommended that resistance seen ISET remain constant while device active (flash spotlight mode). Changing resistance value load current while device active could cause instability.
Input Over-Voltage Protection IOVP included prevent operation high input voltages that could damage device. IOVP circuit senses input voltage determines when supply exceeds Hysteresis included this circuit avoid chattering between states. When voltage rises above this threshold, device disabled until input voltage drops level within specified range. Output Over-Voltage Protection Output prevents SC619 from generating output voltage that could damage other devices connected such load LEDs bypass capacitors. When output voltage exceeds 5.5V, circuit disables charge pump until voltage decreases level within acceptable range. This circuit allows device drive LEDs with high forward voltages reduced level without exceeding output voltage limits specified device. Over-Temperature Protection circuit prevents device from overheating experiencing catastrophic failure. When junction temperature exceeds 150°C device disabled. remains disabled until junction temperature drops below this threshold. Hysteresis included prevent toggling between modes.
Capacitor Selection
SC619 designed low-ESR ceramic capacitors input output bypass capacitors well charge pump bucket capacitors. Ideal performance achieved when exactly equal recommended that ceramic capacitors used best performance.
SC619
Applications Information (continued)
Layout Considerations
following layout suggested two-layer design. capacitors bucket capacitors each conducts full load current 500mA pulsed half clock cycle. output decoupling capacitor placed near VOUT pin. input decoupling capacitor placed near pin. Multiple vias should used whenever necessary change layers nets connecting pins VIN, VOUT, GND, C1-, C1+, C2+. load current return path from ISET sense point through resistor back ground pins. Resistance this path adds total resistance effect reducing current about 10mV drop across return copper trace flash mode. this reason, crucial have resistance return path. Place ground resistor close possible ground SC619. trace from ISET virtually current. ISET trace should make contact power sense resistor minimize effect voltage drop between cathode resistor. Resistor routed with very resistance connection between sense trace between routed around ground vias, allowing shortest ground return path possible. sense trace connected positive terminal most accurate output possible. bottom copper layer mostly ground plane with obstructions between ground vias. smaller rectangle left connects input power input capacitor traces lower left logic inputs FLASH CTRL. trace right ISET sense trace. sense trace routed path returning ground current. while flash spotlight mode. critical maintain adequate ground plane around device maximize heat transfer avoid over-temperature shutdown.
Thermal Resistance Considerations
SC619 package thermally efficient when circuit board layout connects thermal through multiple vias ground plane. thermal resistance rated 49°C/W, this rating dependent connection between thermal ground plane. layout should keep junction temperature below limit while operating SC619 within specified electrical conditions IOUT VISET. poor layout allow junction temperature reach limit
SC619
Outline Drawing MLPD-UT-10
INDICATOR (LASER MARK) SEATING PLANE .007 .074 .042 .114 .012 .018 .000 DIMENSIONS INCHES (.006) .009 .079 .048 .118 .020 .016 .003 .004 .020 0.30 .011 .083 .052 .122 0.18 1.87 1.06 2.90 .024 .002 MILLIMETERS 0.45 0.00 (0.1524) 0.23 2.02 1.21 3.00 0.50 0.40 0.08 0.10 0.50 0.30 2.12 1.31 3.10 0.60 0.05
NOTES: CONTROLLING DIMENSIONS MILLIMETERS (ANGLES DEGREES). COPLANARITY APPLIES EXPOSED WELL TERMINALS.
SC619
Land Pattern MLPD-UT-10
DIMENSIONS INCHES (.112) .075 .055 .087 .020 .012 .037 .150 MILLIMETERS (2.85) 1.90 1.40 2.20 0.50 0.30 0.95 3.80
NOTES: THIS LAND PATTERN REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES MET. THERMAL VIAS LAND PATTERN EXPOSED SHALL CONNECTED SYSTEM GROUND PLANE. FAILURE COMPROMISE THERMAL AND/OR FUNCTIONAL PERFORMANCE DEVICE.
Contact Information
Semtech Corporation Power Management Products Division Flynn Road, Camarillo, 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com
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