AX3902

2/13

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Rev.1.2 Nov.04, 2019



BLOCK DIAGRAM

Oscillator

Slope/

SAW

FB

Bandgap

Error

Amplifier

PWM

Comparator

PWM

PSM

Logic

DHI

BST/

Urive

DLI

HG

LG

Current Sense

Amplifer

VIN

BS

SW

GND

M1

M2

MSENSE

IZERO

Clamp



PIN ASSIGNMENT

The packages of AX3902 are SOT-23-6L; the pin assignment is given by:



ORDER/MARKING INFORMATION

Order Information

Top Marking

Packing

A : Taping

X X

C: SOT-23-6L Blank: Tube

Package Type

AX3902

d

WW: 01~26(A~Z)

27~52(a~z)

ID code: internal

AX3902

Z Y W X

Year: 8=2018

9=2019

B=2020

C=2021

D=2022

:

Z=2044

(Top View)

SOT-23-6L

3

6

4

1

SW

FB

GND

BS

5

VIN

EN

2

Name

Description

GND

Ground

This is the reference of the ground connection for all

components in the power supply.

SW

Power Switch Output

This is the output of a power MOSFET switch.

VIN

Power Supply

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

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.

EN

Enable (floating of this pin not recommended)

This input provides an electrical ON/OFF control of the power

supply.

BS

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.