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LTC3218 400mA Single Wire Camera LED Charge Pump FEATURES

DESCRIPTION
The LTC(R)3218 is a low-noise, high-current charge pump DC/DC converter capable of driving high current LEDs at up to 400mA from a 2.9V to 4.5V input. A low external parts count (one flying capacitor, two programming resistors and two bypass capacitors at VIN and CPO) make the LTC3218 ideally suited for small, battery-powered applications. Built-in soft-start circuitry prevents excessive inrush current during start-up. High switching frequency enables the use of small external capacitors. A built-in 2-second timer protects the LED during flash mode. Output current level is programmed by an external resistor. LED current is regulated using an internal high side 220m sense resistor. Automatic mode switching optimizes efficiency by monitoring the voltage across the charge pump and switching modes only when dropout is detected. The part is available in a low profile 3mm x 2mm 10-lead DFN package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 6411531.

Low Noise Constant-Frequency Operation Multi-Mode Operation: 1x or 2x Boost Mode Automatic Mode Switching High Output Current: 150mA (Continuous), 400mA (Pulsed) From Li-Ion/Polymer Input 2-Second Flash Current Timeout for LED Protection Automatic Soft-Start Output Disconnect No Inductors 220m Internal High Side Current Sense Resistor Single Resistor Programming Capability Tiny Application Circuit (3mm x 2mm DFN Package, All Components < 1mm High)
APPLICATIONS
LED Torch/Flash Supply for DSCs/Cellphones
TYPICAL APPLICATION
Efficiency vs VIN
2.2F 100 90 CP 2.9V TO 4.5V 2.2F VIN CM CPO LTC3218 ILED GND ISETT LED AOT2015 50 40 2.9 4.7F EFFICIENCY (%) 80 70 60 50mA 150mA 300mA 3.1 3.3 3.5 3.7 VIN (V)
3218 TA01b
DISABLED DISABLED
ENABLED ENABLED
ENF ENT ISETF
ENF 0 0 1 1
ENT 0 1 0 1
ILED 0 (SHUTDOWN) 100mA (TORCH) 290mA 390mA (FLASH)
3218 TA01
10.2k 1%
3.9
4.1
4.3
4.5
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LTC3218 ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW CP 1 CPO 2 ILED 3 ENT 4 ISETT 5 11 10 VIN 9 8 7 6 CM GND ENF ISETF
VIN to GND ................................................... -0.3V to 6V CPO to GND ................................................ -0.3V to 6V ENF, ENT .......................................... -0.3V to VIN + 0.3V ICPO, IILED (Note 2) ...............................................500mA CPO Short-Circuit Duration .............................. Indefinite Storage Temperature Range................... -65C to 125C Operating Temperature Range (Note 3) ... -40C to 85C
DDB PACKAGE 10-LEAD (3mm x 2mm) PLASTIC DFN TJMAX = 125C, JA = 76C/W EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH LTC3218EDDB#PBF TAPE AND REEL LTC3218EDDB#TRPBF PART MARKING LCHS PACKAGE DESCRIPTION 10-Lead (3mm x 2mm) Plastic DFN TEMPERATURE RANGE -40C to 85C 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/
ELECTRICAL CHARACTERISTICS
PARAMETER Input Power Supply VIN Operating Voltage IVIN Operating Current IVIN Shutdown Current LED Current Torch Current Ratio (ILED/ISET) Flash Current Ratio (ILED/ISET) Flash Current Ratio (ILED/ISET) ILED Dropout Voltage (VILED) Mode Switching Delay (LED Warm-Up Time) Turn-On Time Minimum LED Forward Voltage
The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C, VIN = 3.6V, CIN = CFLY = 2.2F, CCPO = 4.7F, ENF = HIGH, unless otherwise noted.
CONDITIONS
MIN 2.9
TYP
MAX 4.5
UNITS V A mA
ICPO = 0mA, 1x Mode ICPO = 0mA, 2x Mode ENF = ENT = LOW, VCPO = 0V ILED = 50mA ENT = HIGH, ENF = LOW ILED = 150mA ENT = LOW, ENF = HIGH ILED = 150mA ENT = ENF = HIGH Mode Switching Threshold, (VCPO - VILED), ILED = 100mA ENF, ENT ILED = 50mA to LED Current On

980 1.7 1.1 765 2205 2970 850 2450 3300 7 0.5 160 2.2 3 935 2695 3630
A A/A A/A A/A mV ms s V
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LTC3218 ELECTRICAL CHARACTERISTICS
PARAMETER Charge Pump (CPO) Charge Pump Output Clamp Voltage 1:1 Mode Output Impedance 1:2 Mode Output Impedance CLK Frequency ENF, ENT High Level Input Voltage (VIH) Low Level Input Voltage (VIL) Input Current (IIH) Input Current (IIL) Flash Timeout ISETF, ISETT VISET IISET ISET = 110A ENT = LOW, ENF = HIGH

The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C, VIN = 3.6V, CIN = CFLY = 2.2F, CCPO = 4.7F, ENF = HIGH, unless otherwise noted.
CONDITIONS MIN TYP 5.3 1.3 7 1 1.4 0.4 14.4 -1 2 1.18 1.21 1.24 181 30 1 MAX UNITS V MHz V V A A s V A
VEN = 3.6V VEN = 0V ENF = HIGH

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 150mA. Note 3: The LTC3218E is guaranteed to meet performance specifications from 0C to 85C. Specifications over the -40C to 85C ambient operating temperature range are assured by design, characterization and correlation with statistical process controls.
TYPICAL PERFORMANCE CHARACTERISTICS
ILED Dropout Voltage vs LED Current
0.009 0.008 DROPOUT VOLTAGE (V) 0.007 0.006 ILED (mA) 0.005 0.004 0.003 0.002 0.001 0 0 200 300 100 LED CURRENT (mA) 400
3218 G01
TA = 25C, unless otherwise noted.
ILED vs RSET
450 400 350 300 250 200 150 100 50 0 0 50 100 150 200 RSET (k) 250 300 350 VIN SHUTDOWN CURRENT (A) TORCH FLASH (ENT = LOW, ENF = HIGH) FLASH (ENT = ENF = HIGH) 3.0 2.5 2.0
VIN Shutdown Current vs VIN
T = 25C
T = -40C 1.5 T = 85C 1.0 0.5 0 2.9
3.1
3.3
3.5
3.7 VIN (V)
3.9
4.1
4.3
4.5
3218 G02
3218 G03
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LTC3218 TYPICAL PERFORMANCE CHARACTERISTICS
1x Mode Charge Pump Open-Loop Output Resistance vs Temperature
1.8 OPEN-LOOP OUTPUT RESISTANCE () 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 -40 -15 35 10 TEMPERATURE (C) 60 85
3218 G04
TA = 25C, unless otherwise noted.
2x Mode Charge Pump Open-Loop Output Resistance (2VIN - VCPO)/ICPO vs Temperature
10 OPEN-LOOP OUTPUT RESISTANCE () 9 8 FREQUENCY (kHz) 7 6 5 4 3 2 1 0 -40 -15 35 10 TEMPERATURE (C) 60 85
3218 G05
Oscillator Frequency vs VIN
1100 1080 T = -40C 1060 1040 1020 T = 85C 1000 980 960 2.9 T = 25C
ICPO = 50mA VIN = 2.9V
VIN = 3.6V
VIN = 3.6V VIN = 4.5V
3.1
3.3
3.5
3.7 VIN (V)
3.9
4.1
4.3
4.5
3218 G06
Torch Mode ILED/ISET Current Ratio vs ILED Current
1400 1300 1200 CURRENT RATIO CURRENT RATIO 1100 1000 900 800 700 600 500 400 50 60 70 80 90 100 110 120 130 140 150 ILED CURRENT (mA)
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Flash ILED/ISET Current Ratio vs ILED Current (ENT = LOW, ENF = HIGH)
3500 3300 3100 CURRENT RATIO 2900 2700 2500 2300 2100 1900 1700 1500 100 150 250 300 200 ILED CURRENT(mA) 350 400 4500 4300 4100 3900 3700 3500 3300 3100 2900 2700
Flash ILED/ISET Current Ratio vs ILED Current (ENT = ENF = HIGH)
2500 100
150
250 300 200 ILED CURRENT(mA)
350
400
3218 G08
3218 G09
Torch Mode ILED Current vs VIN
160 140 RSETT = 7.49k 120 ILED (mA) ILED (mA) 100 80 60 40 20 0 2.9 3.1 3.3 3.5 3.7 VIN (V)
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Flash Mode ILED Current vs VIN (ENT = ENF = HIGH)
450 RSETF = 10.2k 400 350 300 ILED (mA) 450 400 350 300 250 200 RSETF = 20k
Flash Mode ILED Current vs VIN (ENT = LOW, ENF = HIGH)
RSETF = 7.49k
RSETF = 10.2k
RSETT = 10.2k
250 200 150 100 50 RSETF = 40.2k
RSETT = 20k RSETT = 40.2k
RSETF = 20k 150 100 50 RSETF = 40.2k
3.9
4.1
4.3
4.5
0 2.9
3.1
3.3
3.5
3.7 VIN (V)
3.9
4.1
4.3
4.5
0 2.9
3.1
3.3
3.5
3.7 VIN (V)
3.9
4.1
4.3
4.5
3218 G11
3218 G12
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LTC3218 TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs VIN
100 90 EFFICIENCY (%) 80 70 60 50 40 2.9
TA = 25C, unless otherwise noted.
2x Mode CPO Output Ripple
50mV/DIV AC COUPLED
50mA 100mA 150mA 200mA 300mA 3.1 3.3 3.5 3.7 VIN (V)
3218 G13
VIN = 3.6V ICPO = 200mA 4.5
500ns/DIV
3218 G14
3.9
4.1
4.3
PIN FUNCTIONS
CP, CM (Pin 1, Pin 9): Charge Pump Flying Capacitor. A 2.2F X5R or X7R ceramic capacitor should be connected from CP to CM. CPO (Pin 2): Output of the Charge Pump. This pin may be enabled or disabled using the ENT and ENF inputs. A 4.7F X5R or X7R ceramic capacitor is required from CPO to GND. ILED (Pin 3): LED Current Output. The LED is connected between ILED (anode) and GND (cathode). The current out of the ILED pin is set by resistors connected to the ISETT and ISETF pins. An internal, 220m sense resistor is connected between CPO and ILED ENT (Pin 4): Input. The ENT pin is used to enable the part into torch mode and bring it into shutdown mode. An internal 250k resistor pulls this pin to GND when left floating. ISETT (Pin 5): LED Torch Current Programming Resistor. A resistor connected between this pin and GND is used to set the LED torch current level. ISETF (Pin 6): LED Flash Current Programming Resistor. A resistor connected between this pin and GND is used to set the LED flash current level. ENF (Pin 7): Input. The ENF pin is used to enable the part into flash mode and bring it into shutdown mode. An internal 250k resistor pulls this pin to GND when left floating. A safety timer will disable the part if this pin is held high for more than 2 seconds. GND (Pin 8): Ground. This pin should be connected directly to a low impedance ground plane. VIN (Pin 10): Power. Supply voltage for the LTC3218. VIN should be bypassed with a low impedance ceramic capacitor to GND of at least 1.6F of capacitance. Exposed Pad (Pin 11): Ground. This pad must be soldered to a low impedance ground plane for optimum thermal performance.
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LTC3218 BLOCK DIAGRAM
CP 1 CM 9
2 CPO OSCILLATOR 106 220m
+
VOLTAGE CLAMP
-
MODE CONTROL
3 ILED
VIN 10
VREF
ENT 4 ENF 7
CONTROL LOGIC
CURRENT SOURCE CONTROL
ISETT 5 6
ISETF 8
GND
GND 11
3218 BD
OPERATION
The LTC3218 uses a switched capacitor charge pump to power a high current LED with a programmed regulated current. Current regulation is achieved using an internal current sense resistor connected between the CPO and ILED pins. The part starts up in 1x mode after a soft-start period. In this mode, VIN is connected to the CPO through switches, the strengths of which are modulated to achieve the desired LED current. This mode provides maximum efficiency and minimum noise. The LTC3218 will remain in this mode until the LED forward voltage (VF) approaches the maximum CPO voltage possible in this mode. When this dropout condition occurs, the LTC3218 will switch to 2x mode after a soft-start period. The current delivered to the LED load is controlled by the internal programmable current source. The current is programmed by resistors connected between the ISETT and ISETF pins and GND. The resistor values needed to
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LTC3218 OPERATION
attain the desired current level can be determined by Equations 1 and 2: 3300 * 1 . 21V R SETF = (1) ILED R SETT 850 * 1 . 21V = ILED (2) Thermal Protection The LTC3218 has built-in overtemperature protection. Thermal shutdown circuitry will shut down the part when the junction temperature exceeds approximately 165C. It will re-enable the part once the junction temperature drops back to approximately 150C. The LTC3218 will cycle in and out of thermal shutdown indefinitely without latchup or damage until the heat source is removed. ENF Timeout The ENF input is used to select the high current setting for use as a camera flash. To prevent damage to the LED, the ENF pin has a 2-second timeout. If the LTC3218 is enabled for greater than approximately 2 seconds using the ENF pin, the part will enter a low-power mode, preventing current from being delivered to the LED. Normal operation can be restored by bringing the part into shutdown and re-enabling it. Short-Circuit Protection When ENF or ENT are brought high, the part will connect VIN and CPO through a weak pull-up. If the CPO capacitor fails to charge up to over 1V (i.e., CPO is shorted), the chip will not be enabled. Similarly, during operation if CPO is pulled down below 1V, the part will be disabled. Soft-Start To prevent excessive inrush current during start-up and mode switching, the LTC3218 employs built-in soft-start circuitry. Soft-start is achieved by increasing the amount of current available to the output charge storage capacitor linearly over a period of approximately 80s.
Table 1. Output Current Modes for All ENT and ENF Settings
ENF LOW LOW HIGH HIGH ENT LOW HIGH LOW HIGH ILED SHUTDOWN 1029/RSETT 2965/RSETF 3993/RSETF
Overcurrent shutdown mode will prevent damage to the part and LED by shutting down the high power sections of the chip. Choosing an RSETF or RSETT value of 5k or greater will ensure that the part stays out of this mode. Regulation is achieved by sensing the voltage at the ILED pin and modulating the charge pump strength based on the error signal. In shutdown mode all circuitry is turned off and the LTC3218 draws a very low current from the VIN supply. The output is disconnected from VIN and is pulled down by a resistance of approximately 90k. The LTC3218 enters shutdown mode when the ENF and ENT pins are brought low. LED Current Programming The LTC3218 includes an accurate, programmable current source that is capable of driving LED currents up to 150mA continuously and up to 400mA for pulsed operation. Pulsed operation may be achieved by toggling the ENT or ENF pins. In either continuous or pulsed operation, proper board layout is required for effective heat sinking. The output current of the LTC3218 is programmed using external resistors connected between the ISETT and ISETF pins and GND. The output current modes are shown in Table 1, where RSETT is connected between ISETT and GND, and RESTF is connected between ISETF and GND. Since the LTC3218 has three separate LED current ratios built in, it can be programmed using a single resistor by connecting ISETT and ISETF together, and then connecting the pins to the resistor.
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LTC3218 OPERATION
Charge Pump Strength When the LTC3218 operates in 2x mode, the charge pump can be modeled as a Thevenin-equivalent circuit to determine the amount of current available from the effective input voltage and effective open-loop output resistance, ROL (Figure 1). ROL is dependent on a number of factors including the oscillator frequency, flying capacitor values and switch resistances. From Figure 1, we can see that the output current is proportional to: 2VIN - CPO ROL (3) in 2x mode.
+ -
2VIN ROL
Mode Switching The LTC3218 will automatically switch from 1x mode to 2x mode whenever the LED forward voltage approaches the maximum CPO voltage for that mode. The part will wait approximately 500s before switching to the next mode. This delay allows the LED to warm up and reduce its forward voltage which may remove the dropout condition. The part may be reset to 1x mode by bringing the part into shutdown by setting the ENF and ENT pins low. Once these pins are low, either one or both may be immediately brought high to re-enable the part.
+
CPO
-
3218 F01
Figure 1. Charge Pump Open-Loop Thevenin-Equivalent Circuit
APPLICATIONS INFORMATION
VIN, CPO Capacitor Selection The value and type of capacitors used with the LTC3218 determine several important parameters such as regulator control loop stability, output ripple, charge pump strength and minimum start-up time. To reduce noise and ripple, it is recommended that low equivalent series resistance (ESR) ceramic capacitors be used for both CVIN and CCPO. Tantalum and aluminum capacitors are not recommended because of their high ESR. The value of CCPO directly controls the amount of output ripple for a given load current. Increasing the size of CCPO will reduce the output ripple at the expense of higher startup current. The peak-to-peak output ripple for 2x mode is approximately given by the expression: IOUT VRIPPLE(P -P) = 2fOSC * CCPO Where fOSC is the LTC3218's oscillator frequency (typically 1MHz) and CCPO is the output storage capacitor. Both the style and value of the output capacitor can significantly affect the stability of the LTC3218. As shown in the Block Diagram, the LTC3218 uses a control loop to adjust the strength of the charge pump to match the current required at the output. The error signal of this loop is stored directly on the output charge storage capacitor. The charge storage capacitor also serves as the dominant pole for the control loop. To prevent ringing or instability, it is important for the output capacitor to maintain at least 3F of actual capacitance over all conditions. Likewise, excessive ESR on the output capacitor will tend to degrade the loop stability of the LTC3218. To prevent poor load transient response and instability, the ESR of the output capacitor should be kept below 80m. Multilayer ceramic chip capacitors typically have exceptional ESR
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LTC3218 APPLICATIONS INFORMATION
performance. MLCCs combined with a tight board layout will yield very good stability. As the value of CCPO controls the amount of output ripple, the value of CVIN controls the amount of ripple present at the input pin (VIN). The input current to the LTC3218 will be relatively constant while the charge pump is on either the input charging phase or the output charging phase but will drop to zero during the clock nonoverlap times. Since the nonoverlap time is small (~15ns), these missing "notches" will result in only a small perturbation on the input power supply line. Note that a higher ESR capacitor such as tantalum will have higher input noise due to the input current change times the ESR. Therefore, ceramic capacitors are again recommended for their exceptional ESR performance. Input noise can be further reduced by powering the LTC3218 through a very small series inductor as shown in Figure 2. A 10nH inductor will reject the fast current notches, thereby presenting a nearly constant current load to the input power supply. For economy, the 10nH inductor can be fabricated on the PC board with about 1cm (0.4) of PC board trace.
10nH VIN 0.1F 2.2F GND
3218 F02
to 85C whereas a Z5U or Y5V style capacitor will lose considerable capacitance over that range. Z5U and Y5V capacitors may also have a very poor voltage coefficient causing them to lose 60% or more of their capacitance when the rated voltage is applied. Therefore, when comparing different capacitors, it is often more appropriate to compare the amount of achievable capacitance for a given case size rather than comparing the specified capacitance value. For example, over rated voltage and temperature conditions, a 1F, 10V, Y5V ceramic capacitor in a 0603 case may not provide any more capacitance than a 0.22F, 10V, X7R available in the same case. The capacitor manufacturer's data sheet should be consulted to determine what value of capacitor is needed to ensure minimum capacitances at all temperatures and voltages. Table 1 shows a list of ceramic capacitor manufacturers and how to contact them.
Table 1. Recommended Capacitor Vendors
AVX Kemet Murata Taiyo Yuden Vishay www.avxcorp.com www.kemet.com www.murata.com www.t-yuden.com www.vishay.com www.tdk.com
LTC3218
TDK
Layout Considerations and Noise Due to the high switching frequency and the transient currents produced by the LTC3218, careful board layout is necessary. A true ground plane and short connections to all capacitors will improve performance and ensure proper regulation under all conditions. An example of such a layout is shown in Figure 3. The flying capacitor pins, CP and CM, will have very high edge rate waveforms. The large dv/dt on these pins can couple energy capacitively to adjacent PCB runs. Magnetic fields can also be generated if the flying capacitors are not close to the LTC3218 (i.e., the loop area is large). To decouple capacitive energy transfer, a Faraday shield may be used. This is a grounded PCB trace between the sensitive node and the LTC3218 pins. For a high quality AC ground, it should be returned to a solid ground plane that extends all the way to the LTC3218.
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Figure 2. 10nH Inductor Used for Input Noise Reduction (Approximately 1cm of Wire)
Flying Capacitor Selection Warning: Polarized capacitors such as tantalum or aluminum should never be used for the flying capacitors since their voltage can reverse upon start-up of the LTC3218. Ceramic capacitors should always be used for the flying capacitors. The flying capacitor controls the strength of the charge pump. In order to achieve the rated output current it is necessary to have at least 1.6F of actual capacitance for the flying capacitor. Capacitors of different materials lose their capacitance with higher temperature and voltage at different rates. For example, a ceramic capacitor made of X7R material will retain most of its capacitance from -40C
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LTC3218 APPLICATIONS INFORMATION
The following guidelines should be followed when designing a PCB layout for the LTC3218. * The Exposed Pad should be soldered to a large copper plane that is connected to a solid, low impedance ground plane using plated, through-hole vias for proper heat sinking and noise protection. * Input and output capacitors (CIN and CCPO) must also be placed as close to the part as possible. * The flying capacitor must also be placed as close to the part as possible. The traces running from the pins to the capacitor pads should be as wide as possible. * VIN, CPO and ILED traces must be made as wide as possible. This is necessary to minimize inductance, as well as provide sufficient area for high current applications. * LED pads must be large and should be connected to as much solid metal as possible to ensure proper heat sinking. Power Efficiency To calculate the power efficiency () of a white LED driver chip, the LED power should be compared to the input power. The difference between these two numbers represents lost power whether it is in the charge pump or the sense resistor. Stated mathematically, the power efficiency is given by: P LED PIN The efficiency of the LTC3218 depends on the mode in which it is operating. In 1x mode, the LTC3218 regulates the output down to the LED forward voltage required to achieve the desired current by varying the strength of the series switches. This mode provides the optimum efficiency available for a given input voltage and LED forward voltage. The efficiency is approximated by: P V V *I LED = LED LED LED PIN VIN * IIN VIN since the input current will be very close to the LED current.
CFLY
CCPO PIN 1
CIN
RSETT
RSETF
3218 F03
Figure 3. Example Board Layout
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LTC3218 APPLICATIONS INFORMATION
At moderate to high output power, the quiescent current of the LTC3218 is negligible and the expression above is valid. Once dropout is detected at the ILED pin, the LTC3218 enables the charge pump in 2x mode. In 2x boost mode, the efficiency is similar to that of a linear regulator with an effective input voltage of 2 times the actual input voltage. In an ideal 2x charge pump, the power efficiency would be given by: P V *I V IDEAL LED = LED LED LED PIN VIN * 2 * ILED 2VIN Thermal Management For higher input voltages and maximum output current, there can be substantial power dissipation in the LTC3218. If the junction temperature increases above approximately 165C, the thermal shutdown circuitry will automatically deactivate the output. To reduce maximum junction temperature, a good thermal connection to the PC board is recommended. Connecting the Exposed Pad to a ground plane and maintaining a solid ground plane under the device can reduce the thermal resistance of the package and PC board considerably.
PACKAGE DESCRIPTION
DDB Package 10-Lead Plastic DFN (3mm x 2mm) (Reference LTC DWG # 05-08-1722 Rev O)
0.64 0.05 (2 SIDES) 0.70 0.05 2.55 0.05 1.15 0.05 PACKAGE OUTLINE 0.25 0.05 0.50 BSC 2.39 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS PIN 1 BAR TOP MARK (SEE NOTE 6)
3.00 0.10 (2 SIDES)
R = 0.05 TYP
R = 0.115 TYP 6
0.40 0.10 10
2.00 0.10 (2 SIDES) 0.64 0.05 (2 SIDES) 5 0.25 0.05 2.39 0.05 (2 SIDES) BOTTOM VIEW--EXPOSED PAD
1
PIN 1 R = 0.20 OR 0.25 x 45 CHAMFER
(DDB10) DFN 0905 REV O
0.200 REF
0.75 0.05
0.50 BSC
0 - 0.05
NOTE: 1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE
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Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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LTC3218 RELATED PARTS
2.2F CP ENF 0 0 1 1 ENT 0 1 0 1 ILED 0 (SHUTDOWN) 50mA (TORCH) 260mA 350mA (FLASH) DISABLED DISABLED ENABLED ENABLED ENF ENT ISETF 20.5k 1% ISETT 11.4k 1%
3218 TA02
CM CPO 4.7F
2.9V TO 4.5V 2.2F
VIN
LTC3218 ILED GND
LED AOT2015
RELATED PARTS
PART NUMBER DESCRIPTION LTC3200-5 LTC3201 LTC3202 LTC3205 LTC3206 LTC3208 LTC3209 LTC3210/ LTC3210-1 LTC3210-2 LTC3210-3 LTC3214 LTC3215 LTC3216 LTC3217 LTC3251 LTC3440 Low Noise, 2MHz Regulated Charge Pump White LED Driver Low Noise, 1.7MHz Regulated Charge Pump White LED Driver Low Noise, 1.5MHz Regulated Charge Pump White LED Driver Multidisplay LED Controller I2C Multidisplay LED Controller High Current Software Configurable Multidisplay LED Controller 600mA MAIN/CAM LED Controller 500mA MAIN/Camera LED Controller COMMENTS Up to 6 White LEDs, VIN: 2.7V to 4.5V, VOUT(MAX) = 5V, IQ = 8mA, ISD 1A, ThinSOTTM Package Up to 6 White LEDs, VIN: 2.7V to 4.5V, VOUT(MAX) = 5V, IQ = 6.5mA, ISD 1A, 10-Lead MS Package Up to 8 White LEDs, VIN: 2.7V to 4.5V, VOUT(MAX) = 5V, IQ = 5mA, ISD 1A, 10-Lead MS Package 92% Efficiency, VIN: 2.8V to 4.5V, IQ = 50A, ISD 1A, 4mm x 4mm QFN Package 92% Efficiency, 400mA Continuous Output Current. Up to 11 White LEDs in 4mm x 4mm QFN Package 95% Efficiency, VIN: 2.9V to 4.5V, VOUT(MAX): 5.5V, IQ = 280A, ISD < 1A, 5mm x 5mm QFN-32 Package Up to 8 LEDs, 94% Efficiency, VIN: 2.9V to 4.5V, 1x/1.5x/2x Boost Modes, 4mm x 4mm QFN Package Up to 5 LEDs, 95% Efficiency, VIN: 2.9V to 4.5V, 1x/1.5x/2x Boost Modes, Exponential Brightness Control, "-1" Version Has 64-Step Linear Brightness Control, 3mm x 3mm QFN Package Drives 4 MAIN LEDs, 3mm x 3mm QFN Package Drives 3 MAIN LEDs, 3mm x 3mm QFN Package 94% Efficiency, VIN: 2.9V to 4.5V, IQ = 300A, ISD < 2.5A, 500mA Output Current, 10-Lead 3mm x 3mm DFN Package VIN: 2.9V to 4.4V, VOUT(MAX) = 5.5V, IQ = 300A, ISD < 2.5A, 3mm x 3mm DFN Package 93% Efficiency, 1A Output Current, 12-Lead 3mm x 4mm DFN Package, Independent Low/High Current Programming VIN: 2.9V to 4.4V, IQ = 400A, Four Outputs, 3mm x 3mm 16-Lead DFN Package 85% Efficiency, VIN: 3.1V to 5.5V, VOUT: 0.9V to 1.6V, IQ = 9A, ISD 1A, 10-Lead MS Package 95% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN) = 2.5V, IQ = 25A, ISD 1A, 10-Lead MS Package
3218fa LT 0207 REV A * PRINTED IN USA
MAIN/CAM LED Controller with 32-Step Brightness Control MAIN/CAM LED Controller with 32-Step Brightness Control 500mA Camera LED Charge Pump 700mA Low Noise High Current LED Charge Pump 1A Low Noise High Current White LED Driver 600mA Low Noise Multi-LED Camera Light 500mA (IOUT), 1MHz to 1.6MHz Spread Spectrum Step-Down Charge Pump 600mA (IOUT), 2MHz Synchronous BuckBoost DC/DC Converter
ThinSOT is a trademark of Linear Technology Corporation.
12 Linear Technology Corporation
(408) 432-1900 FAX: (408) 434-0507
1630 McCarthy Blvd., Milpitas, CA 95035-7417
www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 2007

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