lt3743 Linear Technology Corporation, lt3743 Datasheet - Page 10

• Manufacturer Part Number: lt3743
• Description: High Current Synchronous Step-down Led Driver With Three-state Control
• Manufacturer: Linear Technology Corporation

LT3743
PIN FUNCTIONS
PWMGL (Pin 22/Pin 23): The PWMGL output pin drives
the gate of an external FET to connect one of the switch-
ing regulator output capacitors to the load. The output
impedance is approximately 2.5Ω.
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 impedance is 2.5Ω.
SW (Pin 24/Pin 25): The SW pin is used internally as the
lower rail for the fl oating high side driver. Externally, this
node connects the two power FETs and the inductor.
CBOOT (Pin 25/Pin 26): The CBOOT pin provides a fl oat-
ing 5V regulated supply for the high side FET driver. An
external Schottky diode is required from the V
to the CBOOT pin to charge the C
switch pin is near ground.
10
(QFN/TSSOP)
BOOT
capacitor when the
CC_INT
pin
LG (Pin 26/Pin 28): LG is the bottom FET gate drive signal
that controls the state of the low side external power FET.
The driver impedance is 2.5Ω.
V
the C
the digital and switching subcircuits. Below 6V V
this pin to the rail. V
Shutdown operation disables the output voltage drive.
V
bypassed with a 1μF low ESR capacitor to ground.
CC_INT
IN
(Pin 28/Pin 3): Input Supply Pin. Must be locally
BOOT
(Pin 27/Pin 1): A regulated 5V output for charging
capacitor. V
CC_INT
CC_INT
is current limited to ≈50mA.
also provides the power for
IN
, tie
3743f