AAT1143
1MHz 400mA Step-Down Converter
1143.2005.09.1.7 1
SwitchReg
™
General Description
The AAT1143 SwitchReg™ is a member of
AnalogicTech's Total Power Management IC™
(TPMIC™) product family. It is a 1MHz step-down
converter with an input voltage range of 2.7V to
5.5V and output as low as 0.6V. Its low supply cur-
rent, small size, and high switching frequency
make the AAT1143 the ideal choice for portable
applications.
The AAT1143 is available in either a fixed version
with internal feedback or a programmable version
with external feedback resistors. It can deliver
400mA of load current while maintaining a low
25µA no load quiescent current. The 1MHz switch-
ing frequency minimizes the size of external com-
ponents while keeping switching losses low. The
AAT1143 feedback and control delivers excellent
load regulation and transient response with a small
output inductor and capacitor.
The AAT1143 is designed to maintain high efficien-
cy throughout the operating range, which is critical
for portable applications.
The AAT1143 is available in a space-saving
2.0x2.1mm SC70JW-8 package and is rated over
the -40°C to +85°C temperature range.
Features
•V
IN
Range: 2.7V to 5.5V
•V
OUT
Adjustable Down to 0.6V
— Fixed or Adjustable Version
• 25µA No Load Quiescent Current
• Up to 95% Efficiency
• 400mA Max Output Current
• 1MHz Switching Frequency
• Soft Start
• Over-Temperature Protection
• Current Limit Protection
• 100% Duty Cycle Low-Dropout Operation
• 0.1µA Shutdown Current
• SC70JW-8 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 (Fixed Output Voltage)
AAT1143 Efficiency
(V
OUT
= 2.5V; L = 4.7µH)
Output Current (mA)
Efficiency (%)
60
70
80
90
100
0.1 1 10 100 1000
V
IN
= 3.3V
4.7µH
L1
4.7µF
C1
4.7µF
C2
EN
1
OUT
2
VIN
3
LX
4
AGND
5
PGND
6
PGND
7
PGND
8
AAT1143
U1
V
IN
V
O