LM34910SD datasheet(3/11 Pages) NSC

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Pin Description

NAME

DESCRIPTION

APPLICATION INFORMATION

Switching Node

Internally connected to the buck switch source.

Connect to the external inductor, diode, and boost

capacitor.

BST

Boost pin for boot-strap capacitor

Connect a 0.022 µF capacitor from SW to this pin. An

internal diode charges the capacitor during the

off-time.

SEN

Current sense input

Internally the current sense resistor connects from this

pin to S

GND. Re-circulating current flows out of this pin

to the free-wheeling diode. Current limit is set at

1.25A.

GND

Sense Ground

Re-circulating current flows into this pin to the current

sense resistor.

RTN

Circuit Ground

Ground for all internal circuitry other than the current

limit detection.

Feedback

Internally connected to the regulation and over-voltage

comparators. The regulation level is 2.5V.

Softstart

An internal 11.5 µA current source charges an external

capacitor to 2.5V to provide the softstart function.

ON/SD

On-time Control and Shutdown

An external resistor from V

IN to this pin sets the buck

switch on-time. Grounding this pin shuts down the

regulator.

Output from the start-up regulator

Nominally regulated to 7.0V. An external voltage

(8V-14V) can be connected to this pin to reduce

internal dissipation. An internal diode connects V

CC to

IN.

Input supply voltage

Nominal input range is 8.0V to 36V.

LM34910SD Datasheet(PDF) 3 Page - National Semiconductor (TI)

LM34910SD Datasheet(HTML) 3 Page - National Semiconductor (TI)

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