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Rev.1.1 Nov.05, 2019

AX3984



PIN ASSIGNMENT

The package of AX3984 ; the pin assignment is given by:

1

6

5

3

2

SS

COMP

BST

IN

SW

4

7

8

GND

EN

FB

TOP VIEW

EXPOSED PAD ON BACKSIDE

Name

Description

BST

High Side Gate Drive Boost Input

It is required to connect SW and BST by a capacitor, which is able to boost the

gate drive to the internal NMOS above VIN to fully turn it ON.

VIN

Power Supply

The input voltage for the power supply is connected to this pin.

SW

Power Switch Output

This is the output of a power MOSFET switch.

GND

Ground

This is the reference of the ground connection for all components in the power

Supply.

FB

Voltage Feedback

This is the input to an error amplifier, which drives the PWM controller. It is

necessary to connect this pin to the actual output of power supply to set the DC

output voltage.

COMP

Compensation

This pin is to compensate the regulation control loop by connecting a series of RC

network from COMP pin to GND pin.

EN

Enable (floating of this pin not recommended )

This input provides an electrical ON/OFF control of the power supply. If the EN pin

is open, it will be pulled to high by the internal circuit.

SS

Soft-Start

This pin is connected to an external capacitor, which is between the SS pin and

GND to control soft-start time.

This externally connected 0.1μF capacitor is able to set the soft-start period to

28ms.