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LT3470A

3470afa

SHDN (Pin 8): The SHDN pin is used to put the LT3470A in

shutdown mode. Tie to ground to shut down the LT3470A.

Apply 2V or more for normal operation. If the shutdown

feature is not used, tie this pin to the VIN pin.

NC (Pin 7): This pin can be left ﬂoating, connected to VIN,

or tied to GND.

VIN (Pin 6): The VIN pin supplies current to the LT3470A’s

internal regulator and to the internal power switch. This

pin must be locally bypassed.

GND (Pin 5): Tie the GND pin to a local ground plane

below the LT3470A and the circuit components. Return

the feedback divider to this pin.

SW (Pin 4): The SW pin is the output of the internal power

switch. Connect this pin to the inductor, catch diode and

boost capacitor.

BOOST (Pin 3): The BOOST pin is used to provide a drive

voltage, which is higher than the input voltage, to the

internal bipolar NPN power switch.

BIAS (Pin 2): The BIAS pin connects to the internal boost

Schottky diode and to the internal regulator. Tie to VOUT

when VOUT>2.5VortoVINotherwise.WhenVBIAS>3Vthe

BIAS pin will supply current to the internal regulator.

FB (Pin 1): The LT3470A regulates its feedback pin to

1.25V. Connect the feedback resistor divider tap to this

pin. Set the output voltage according to VOUT = 1.25V (1

+ R1/R2) or R1 = R2 (VOUT/1.25 – 1).

Exposed Pad (Pin 9):

Ground. Must be soldered to PCB.

PIN FUNCTIONS

LDPR Datasheet(PDF) 7 Page - Linear Technology