LTC3214 Datasheet, PDF (5/12 Pages) Linear Technology – 500mA Camera LED Charge Pump

LTC3214
PI FU CTIO S
C2⁺, C1⁺, C2^–, C1^– (Pins 1, 2, 8, 10): Charge Pump Flying
Capacitor Pins. A 2.2µF X5R or X7R ceramic capacitor
should be connected from C1⁺ to C1^– and from C2⁺ to
C2^–.
CPO (Pin 3): Output. CPO is the output of the charge
pump. This pin may be enabled or disabled using the EN
input. A 4.7µF X5R or X7R ceramic capacitor is required
from CPO to GND.
I_LED (Pin 4): Input. I_LED is the LED current sense pin. The
LED is connected between CPO (anode) and I_LED (cath-
ode). The current into the I_LED pin is set by a resistor
connected to the I_SET pin and regulated internally.
I_SET (Pin 5): LED Current Programming Resistor Pin. A
resistor connected between this pin and GND is used to set
the LED current level.
EN (Pin 6): Input. The EN pin is used to enable the part and
bring it into shutdown mode. An internal 250kΩ resistor
pulls this pin to GND when left floating.
V_IN (Pin 7): Power. Supply voltage for the LTC3214. V_IN
should be bypassed with a 2.2µF to 4.7µF low impedance
ceramic capacitor to GND.
GND (Pin 9): Charge Pump Ground. This pin should be
connected directly to a low impedance ground plane.
Exposed Pad (Pin 11): Control Signal Ground. This pad
must be soldered to a low impedance ground plane for
optimum thermal and electrical performance.
BLOCK DIAGRA
2
C1⁺
10
C1^–
1
C2⁺
8
C2^–
OSCILLATOR
V_IN
7
EN
6
CONTROL
LOGIC
250k
GND
9
CPO
3
VOLTAGE
CLAMP
MODE
CONTROL
V_REF
CURRENT
SOURCE
CONTROL
V_IN
I_{LED 4}
58Ω
0.11Ω
I_SET
5
GND
11
3214 BD
3214fa
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