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Preliminary Datasheet

3A, 2MHz High Performance Synchronous Buck Converter AP3433

Jul. 2012 Rev. 1. 1 BCD Semiconductor Manufacturing Limited

General Description

The AP3433 is a current mode, PWM synchronous

buck (step-down) DC-DC converter, capable of

driving a 3A 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 AP3433 can be

programmable from 300kHz 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 AP3433 is available in QFN-3×3-16 package.

Features

• Input Voltage Range: 2.95V to 5.5V

• 0.827V Reference Voltage with ±3% Precision

• Two 45mΩ(typical) MOSFETs for High

Efficiency at 3A Load

• High Efficiency: up to 94%

• Output Current: 3A

• Programmable Frequency:300kHz to 2MHz

• Current Mode Control

• Synchronizes to External Clock

• Adjustable Soft-start

• Soft Start-up into Pre-biased Output

• UV and OV Power Good Output

• Built-in Over Current Protection

• Built-in Thermal Shutdown Function

• Programmable UVLO Function

• Built-in Over Voltage Protection

• Thermally Enhanced 3mm×3mm 16-pin QFN

Applications

• Low-voltage, High-density Power Systems

• Point of Load Regulation for Consumer

Applications such as Set Top Boxes, LCD

Displays, CPE Equipment

Figure 1. Package Type of AP3433

QFN-3×3-16

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