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| LTC3218 Datasheet, PDF (5/12 Pages) Linear Technology – 400mA Single Wire Camera LED Charge Pump | |||
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LTC3218
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted.
Efï¬ciency vs VIN
100
90
80
70
60
50mA
100mA
50
150mA
200mA
300mA
40
2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5
VIN (V)
3218 G13
2x Mode CPO Output Ripple
50mV/DIV
AC COUPLED
VIN = 3.6V
ICPO = 200mA
500ns/DIV
3218 G14
PIN FUNCTIONS
CP, CM (Pin 1, Pin 9): Charge Pump Flying Capacitor. A
2.2µF 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 4.7µF 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, 220mΩ 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 250kΩ resistor pulls this pin to GND when
left ï¬oating.
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 ï¬ash current level.
ENF (Pin 7): Input. The ENF pin is used to enable the
part into ï¬ash mode and bring it into shutdown mode.
An internal 250kΩ resistor pulls this pin to GND when
left ï¬oating. 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 capaci-
tor to GND of at least 1.6µF of capacitance.
Exposed Pad (Pin 11): Ground. This pad must be soldered
to a low impedance ground plane for optimum thermal
performance.
3218fa
5
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