LT3466EDD-1 Ver la hoja de datos (PDF) - Linear Technology

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LT3466EDD-1

White LED Driver and Boost Converter in 3mm × 3mm DFN Package

Linear Technology 

LT3466-1

PI FU CTIO S

VOUT1 (Pin 1): Output of Converter 1. This pin is connected

to the cathode of the internal Schottky diode. Connect an

output capacitor from this pin to ground.

SW1 (Pin 2): Switch Pin for Converter 1. Connect the

inductor at this pin.

VIN (Pin 3): Input Supply Pin. Must be locally bypassed

with a 1µF, X5R or X7R type ceramic capacitor.

SW2 (Pin 4): Switch Pin for Converter 2. Connect the

inductor at this pin.

VOUT2 (Pin 5): Output of Converter 2. This pin is connected

to the cathode of the internal Schottky diode. Connect an

output capacitor from this pin to ground.

FB2 (Pin 6): Feedback Pin for Converter 2. The nominal

voltage at this pin is 800mV. Connect the resistor divider

to this pin. The feedback voltage can be programmed

as:

VFB2 ≈ VCTRL2, when VCTRL2 < 0.8V

VFB2 = 0.8V, when VCTRL2 > 1V

CTRL2 (Pin 7): Dimming and Shutdown Pin for Con-

verter 2. As the pin voltage is ramped from 0V to 1V, the

FB2 pin voltage tracks the CTRL2 voltage and ramps up to

0.8V. Any voltage above 1V does not affect the feedback

voltage. Do not leave the pin floating. It must be connected

to ground to disable converter 2.

RT (Pin 8): Timing Resistor to Program the Switching

Frequency. The switching frequency can be programmed

from 200KHz to 2MHz.

CTRL1 (Pin 9): Dimming and Shutdown Pin for Con-

verter 1. Connect this pin to ground to disable the con-

verter. As the pin voltage is ramped from 0V to 1.8V, the

LED current ramps from 0 to ILED1 (= 200mV/RFB1). Any

voltage above 1.8V does not affect the LED current.

FB1 (Pin 10): Feedback Pin for Converter 1. The nominal

voltage at this pin is 200mV. Connect cathode of the lowest

LED and the feedback resistor at this pin. The LED current

can be programmed by :

ILED1 ≈ (VCTRL1/5 • RFB1), when VCTRL1 < 1V

ILED1 ≈ (200mV/RFB1), when VCTRL1 > 1.8V

Exposed Pad (Pin 11): The Exposed Pad must be soldered

to the PCB system ground.

34661f

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