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LT3502/LT3502A

3502fc

PIN FUNCTIONS

VIN (Pin 1/Pin 10): The VIN pin supplies current to the

LT3502/LT3502A’s internal regulator and to the internal

power switch. This pin must be locally bypassed.

BD (Pin 2/Pin 8): The BD pin is used to provide current

to the internal boost Schottky diode.

FB (Pin 3/Pin 7): The LT3502/LT3502A regulate their

feedback pin to 0.8V. Connect the feedback resistor di-

vider tap to this pin. Set the output voltage according to

VOUT = 0.8(1 + R1/R2). A good value for R2 is 10k.

SHDN (Pin 4/Pin 6): The SHDN pin is used to put the

LT3502 in shutdown mode. Tie to ground to shut down

the LT3502/LT3502A. Tie to 2V or more for normal

operation. If the shutdown feature is not used, tie this pin

to the VIN pin. The SHDN pin also provides soft-start and

frequency foldback. To use the soft-start feature, connect

R3 and C4 to the SHDN pin. SHDN Pin voltage should

not be higher than VIN.

GND (Pin 5/Pin 5): Ground Pin.

DA (Pin 6/Pin 4): Connect the catch diode (D1) anode to

this pin. This pin is used to provide frequency foldback

in extreme situations.

BOOST (Pin 7/Pin 2): The BOOST pin is used to provide a

drive voltage, higher than the input voltage, to the internal

bipolar NPN power switch. Connect a boost capacitor from

this pin to SW Pin.

SW (Pin 8/Pin 1): The SW pin is the output of the internal

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

and boost capacitor.

(DFN/MS)

LCLV Datasheet(PDF) 7 Page - Linear Technology