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Axelite Confidential Materials, do not copy or distribute without written consent.

Rev.1.4 Oct.17, 2019

AX3484

3A, 23V, 340kHz Synchronous Rectified

Step-Down Converter



GENERAL DESCRIPTION

The AX3484 is a monolithic synchronous buck regulator. The device integrates two

100mΩ MOSFETs, and provides 3A of continuous load current over a wide input voltage of

4.75V to 23V. Current mode control provides fast transient response and Cycle-by-Cycle

current limit.

An adjustable soft-start prevents inrush current at turn-on, and in shutdown mode the

supply current drops to 1μA.

This device, available in an 8-pin SOP with exposed pad package, provides a very

compact solution with minimal external components.



FEATURES

- 3A Output Current

- Wide 4.75V to 23V Operating Input Range

- Integrated 100mΩ Power MOSFET Switches

- Output adjust from VFB to 20V

- Up to 95% Efficiency

- Programmable Soft-Start

- Stable with Low ESR Ceramic Output Capacitors

- Fixed 350KHz Frequency

- Cycle-by-Cycle Over Current Protection

- Thermal shutdown and short circuit protections

- RoHS and Halogen free compliance.



BLOCK DIAGRAM

+

-

+

-

+

-

+

-

S

R

Q

Q

+

5

FB

SS



0.925V

EN

EN

1.5V

INTERNAL

REGULATORS

IN

5V

3

4

1

2 IN

5V

BS

SW

GND

M1

0.13Ω

M2

0.13Ω

RAMP

CLK

CURRENT

SENSE

AMPLIFIER

CURRENT

COMPARATOR

SHUTDOWN

COMPARATOR

6μA

ERROR

AMPLIFIER

8

OSCILLATOR

90/350KHz

7

6

COMP

+

-

0.3V

+

-

1.1V

OVP

IN<4.10V

+

-

LOCKOUT

COMPARATOR

2.7V

EN OK

1.2V

OVP