1

AAT1149B

2.2MHz FastTransient 400mA Step-Down Converter

DATA SHEET

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201989B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013

General Description

The AAT1149B SwitchReg is a 2.2MHz step-down con-

verter with an input voltage range of 2.2V to 5.5V. It is

optimized to react quickly to load variations and operate

with a tiny 0603 inductor that is only 1mm tall.

The AAT1149B can deliver 400mA of load current while

maintaining a low 45μA no load quiescent current. The

2.2MHz switching frequency minimizes the size of exter-

nal components while keeping switching losses low.

The AAT1149B maintains high efficiency throughout the

operating range, which is critical for portable applica-

tions.

The AAT1149B is available in a Pb-free, space-saving

5-pin wafer-level chip scale (WLCSP) package and is

rated over the -40°C to +85°C temperature range.

Features

• Ultra-Small 0603 Inductor (Height = 1mm)

• 400mA Max Output Current

• Up to 98% Efficiency

• 45μA No Load Quiescent Current

• 2.2MHz Switching Frequency

• 70μs Soft Start

• Fast Load Transient

• Over-Temperature Protection

• Current Limit Protection

• 100% Duty Cycle Low-Dropout Operation

• <1μA Shutdown Current

• 0.91 x 1.235mm WLCSP Package

• Temperature Range: -40°C to +85°C

Applications

• Cellular Phones

• Digital Cameras

• Handheld Instruments

• Microprocessor / DSP Core / IO Power

• PDAs and Handheld Computers

• USB Devices

Typical Application

L1 2.2µH

C1

4.7µF

C2

4.7µF

EN

FB

IN

LX

AGND

PGND

PGND

PGND

AAT1149B

U1