Description

The AP3440 is a current mode, PWM synchronous buck (step-down) DC-DC converter, capable of driving a 4A load with high efficiency, excellent line and load regulation.

The device integrates two N-channel power MOSFETs with low on-resistance. Current mode control provides fast transient response and cycle-by-cycle current limit.

The switching frequency of AP3440 can be programmable from 200kHz to 2MHz, which allows small-sized components, such as capacitors and inductors. A standard series of inductors from several different manufacturers are available. This feature greatly simplifies the design of switch-mode power supplies.

Under voltage lockout is internally set at 2.6V, but can be increased by programming the threshold with a resistor network on the enable pin. The output voltage startup ramp is controlled by the soft-start pin. An open drain power good signal indicates the output is within 93% to 107% of its nominal voltage.

The AP3440 is available in U-QFN3030-16 package.

Application(s)

Low-voltage, High-density Power Systems
Point of Load Regulation for High Performance DSPs, FPGAs, ASICs and Microprocessors
Broadband, Networking and Optical Communications Infrastructure

Specifications & Technical Documents

Product Parameters

Efficiency (%)	94
Frequency Typ (Hz)	300
HS RDS(ON) (mΩ)	30
LS RDS(ON) (mΩ)	30
MaximumInput Voltage (V)	5.5
MinimumInput Voltage (V)	2.95
Output Current (A)	4
Output Voltage (V)	ADJ
Quiescent Current Typ (μA)	0.36
Shutdown Current Typ (µA)	2
Type	Buck

Technical Documents

Recommended Soldering Techniques

TN1.pdf

Purchase & Availability

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Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN #	Issue Date	Implementation Date	Subject
PCN-2770	2025-10-30	2025-10-30	Add Fab Site Code, Country of Diffusion (COD) and Assembly Site Origin (ASO) on Product and Shipping Labels for all Diodes Products

AP3440 (Obsolete)