AS1333

650mA, Step Down DC/DC Conver ter for Portable Applications

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Revision 1.02

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1 General Description

The AS1333 is a step-down DC-DC converter designed

to power portable applications from a single Li-Ion

battery. The device also achieves high-performance in

mobile phones and other applications requiring low

dropout voltage.

The AS1333 steps down an input voltage of 3.25V to

5.5V to a fixed output voltage of 3.09V.

Fixed-frequency PWM operation minimizes RF

interference. Shutdown function turns the device off and

reduces battery consumption to 0.01µA (typ.).

The AS1333 is available in a 8-pin WL-CSP package. A

high switching frequency (2 MHz) allows use of tiny

surface-mount components. Only three small external

surface-mount components, an inductor and two

ceramic capacitors are required.

2 Key Features

!

PWM Switching Frequency: 2MHz

!

Single Lithium-Ion Cell Operation

!

Fixed Output Voltage (3.09V)

!

Maximum load capability of 650mA

!

400mA) from internal synchronous rectification

!

Current Overload Protection

!

Thermal Overload Protection

!

Soft Start

!

Low Dropout Voltage (140 m

Ω Typ PFET)

!

8-pin WL-CSP

3 Applications

The AS1333 is an ideal solution for cellular phones,

hand-held radios, RF PC cards, battery powered RF

devices, and RFIC chipsets.

Figure 1. Typical Application Circuit

AS1333

PGND

AGND

NC

EN

PVIN

VDD

SW

FB

3.09V

10 µF

3.3 µH

10 µF