AAT2749 Datasheet, PDF (1/17 Pages) Skyworks Solutions Inc. – 3.0MHz Step-Down Converter and Low-V in LDO

DATA SHEET
AAT2749
3.0MHz Step-Down Converter and Low-V_IN LDO
General Description
The AAT2749 is a two channel power regulator that oper-
ates from 2.3V to 5.5V. The AAT2749 contains a 3.0MHz,
600mA step-down converter and a low input voltage
300mA LDO regulator.
The step-down converter can deliver 600mA of load cur-
rent. The 3.0MHz switching frequency minimizes the size
of external components while keeping switching losses
low. The AAT2749 step-down converter maintains high
efficiency throughout the operating range, which is criti-
cal for portable applications. Fixed frequency, low noise
operation can be forced by a logic signal on the MODE
pin.
The AAT2749 also contains a 300mA LDO regulator with
input voltage capability as low as 1.62V. The LDO regula-
tor power input can be tied directly to the output of the
step-down regulator to increase efficiency.
Total quiescent current for the step-down converter and
LDO is a low 100μA under no load condition.
The AAT2749 is available in a Pb-free, space-saving
9-pin chip scale package (CSP) (200μm bump in 400μm
pitch) and is rated over the -40°C to +85°C temperature
range.
Features
• V_IN Range: 2.3V to 5.5V
• Two Outputs
▪ VOUT_BUCK = 1.8V
▪ VOUT_LDO = 1.0V, 1.2V
• Step-Down Converter
▪ Ultra-Small 0603 Inductor (Height 1mm)
▪ Up to 92% Efficiency
▪ 3.0MHz Switching Frequency
▪ MODE Selection Pin to Select Forced PWM or PWM/
LL Operation Mode
▪ ^{Current Limit Protection}
▪ Automatic Soft Start
• LDO Regulator
▪ VINL Range: 1.62V to VIN
▪ 300mA Output Current
▪ Current Limit Protection
• 100μA No Load Quiescent Current
• Over-Temperature Protection
• -40°C to +85°C Temperature Range
Applications
• Battery-Powered Applications
• Cellular and Smart Phones
• Digital Still and Video Cameras
• PDAs, Palmtops
• Portable Instruments
Typical Application
(2.3V - 5.5V)
(1.62V - 5.5V)
IN_BUCK
C_{IN_BUCK}
4.7μF
LX
OUT_BUCK
IN_LDO OUT_LDO
C_{IN_LDO}
1.0μF
AAT2749
CHIP_ENABLE
MODE
GND
2.2μH
1.8V: 600mA
C_BUCK
4.7μF
1.2V: 300mA
C_LDO
2.2μF
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
202037A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 8, 2012
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