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Rev.1.4 Oct.17, 2019

AX3484



PIN ASSIGNMENT

The package of AX3484 is SOP-8L-EP; the pin assignment is given by:

( Top View )

1

2

3

4

8

7

6

5

SOP-8L-EP

GND

BS

SW

GND

IN

COMP

EN

SS

FB

Name

Description

BS

High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel

MOSFET switch. Connect a 0.01μF or greater capacitor from SW to BS to power the

high side switch.

IN

Power Input. IN supplies the power to the IC, as well as the step-down converter

switches. Drive IN with a 4.75V to 23V power source. Bypass IN to GND with a suitably

large capacitor to eliminate noise on the input to the IC. See Input Capacitor.

SW

Power Switching Output. SW is the switching node that supplies power to the output.

Connect the output LC filter from SW to the output load. Note that a capacitor is required

from SW to BS to power the high-side switch.

GND Ground.

FB

Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a

resistive voltage divider from the output voltage. The feedback threshold is 0.925V. See

Setting the Output Voltage.

COMP

Compensation Node. COMP is used to compensate the regulation control loop. Connect

a series RC network from COMP to GND to compensate the regulation control loop. In

some cases, an additional capacitor from COMP to GND is required. See Compensation

Components.

EN

Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn

on the regulator, drive it low to turn it off. Pull up with 100kΩ resistor for automatic

startup.

SS

Soft-Start Control Input. SS controls the soft start period. Connect a capacitor from SS to

GND to set the soft-start period. A 0.1μF capacitor sets the soft-start period to 15ms. To

disable the soft-start feature, leave SS unconnected.