LT3743(RevB) Ver la hoja de datos (PDF) - Linear Technology

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Fabricante

LT3743
(Rev.:RevB)

High Current Synchronous Step-Down LED Driver with Three-State Control

Linear Technology 

LT3743

PIN FUNCTIONS (QFN/TSSOP)

PWMGL (Pin 22/Pin 23): The PWMGL output pin drives

the gate of an external FET to connect one of the switching

regulator output capacitors to the load. The driver pull-up

impedance is 3.2Ω and pull-down impedance is 1.75Ω.

HG (Pin 23/Pin 24): HG is the top FET gate drive signal

that controls the state of the high side external power

FET. The driver pull-up impedance is 2.3Ω and pull-down

impedance is 1.3Ω.

SW (Pin 24/Pin 25): The SW pin is used internally as the

lower rail for the floating high side driver. Externally, this

node connects the two power FETs and the inductor.

CBOOT (Pin 25/Pin 26): The CBOOT pin provides a float-

ing 5V regulated supply for the high side FET driver. An

external Schottky diode is required from the VCC_INT pin

to the CBOOT pin to charge the CBOOT capacitor when the

switch pin is near ground.

LG (Pin 26/Pin 28): LG is the bottom FET gate drive sig-

nal that controls the state of the low side external power

FET. The driver pull-up impedance is 2.5Ω and pull-down

impedance is 1.3Ω.

VCC_INT (Pin 27/Pin 1): A regulated 5V output for charging

the CBOOT capacitor. VCC_INT also provides the power for

the digital and switching subcircuits. Below 6V VIN, tie

this pin to the rail. VCC_INT is current limited to ≈50mA.

Shutdown operation disables the output voltage drive.

VIN (Pin 28/Pin 3): Input Supply Pin. Must be locally

bypassed with a 1μF low ESR capacitor to ground.

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