LTC3215 Datasheet, PDF (5/12 Pages) Linear Technology – 700mA Low Noise High Current LED Charge Pump

LTC3215
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): Output. I_LED is the LED current source output.
The LED is connected between CPO (anode) and I_LED
(cathode). The current into the I_LED pin is set by the
programming resistor connected from I_SET to GND.
I_SET (Pin 5): LED Current Programming Resistor Pin. The
I_SET pin will servo to 1.22V. A resistor connected between
this pin and GND is used to set the LED current level.
Connecting a resistor of 2k or less will cause the LTC3215
to enter overcurrent shutdown mode.
EN (Pin 6): Input. The EN is used to enable the part or put
it into shutdown mode.
V_IN (Pin 7): Power. Supply voltage for the LTC3215. V_IN
should be bypassed with a 2.2µF or greater 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
GND
9
1X MODE: CPO = V_IN
1.5X MODE: CPO = 4.6V
2X MODE: CPO = 5.1V
CPO ₃
V_REF
MODE
CONTROL
DROPOUT
DETECTOR
I_LED
4
CURRENT
SOURCE
CONTROL
I_SET
5
GND
11
3215 BD
3215f
5