[AP3440]

016008997-E-00

2016/10

- 1 -

1. General Description

The AP3440 is a synchronous rectification PWM control step-down DC-DC converter of the current

mode with excellent transient load response characteristics. The recommended operational

temperature ranges from

−40 to 125ºC. It is capable for automotive use that demands high reliability.

The AP3440 supports input voltage from 4.1V to 5.5V and its output voltage is 1.227V. It integrates

power MOSFET corresponding to a 4.5A output current at the maximum. The AP3440 is equipped with

Output Over-Current Protection, Output Over-Voltage Protection, Under Voltage Lock Out, Thermal

Protection, and Power-good function. The AP3440 is housed in a 28-pin QFN0505 package.

2. Features

Input Voltage Range

: 4.1V ~ 5.5V

Output Voltage

: 1.227V (+1.96%,

−1.79%)

Output Current Peak

: 4.5A

Oscillation Frequency

: 2100 kHz

External Synchronization (supporting Master/Slave mode), Frequency Range : 1800kHz ~ 2250kHz

Integrated Power MOSFET

Soft Start Function

High-Accurate Power-Good Function

Discharging Function of Output Capacitor

Protection Functions: Over Current, Over Voltage, Under Voltage Lock Out and Thermal Protections

Recommended Operational Temperature Range: Ta=

−40 ~ 125ºC

Package: 28-pin QFN0505 (Exposed Pad and Pins are Plated)

High-Accurate Step-Down

AP3440ABN122

Figure 1. Application

Vin

Vout

C1

SGND

SW1

SW2

FSIN

SW3

CC

SW4

SW5

AP3440

EN

EN

SW6

VO1

PG

SS

NC

VO2

C5

R1

C2

L1

C3

C4

DC-DC Converter with 4.5A MOSFET