PRODUCT DATASHEET
AAT1275
SwitchReg
TM
General Description
The AAT1275 SwitchReg is a 2MHz, 500mA synchronous
boost converter with an integrated current-limiting load
switch controlled output. The AAT1275 operates from a
single-cell Lithium-ion/ polymer battery source and pro-
vides a regulated 5V, current limit controlled output to
support USB port V
BUS
applications in portable consumer
electronic products. The AAT1275 can support both USB
2.0 host port and USB on-the-go operation, as well as
general purpose applications where a 5V supply with a
user programmable current limit is needed.
The high efficiency boost converter section of the
AAT1275 is typically set for a 5V output and can deliver
up to 500mA load current to support USB V
BUS
operation
from an input supply as low as 2.7V. The high boost
converter switching frequency (up to 2.0MHz) provides
fast load transient and allows the use of small external
components. Fully integrated control circuitry simplifies
system design and reduces total solution size.
The integrated, programmable current limiting load
switch provides USB port protection for portable devices
allowing the AAT1275 to supply a 5V USB V
BUS
up to
500mA. The load switch provides an active low fault flag
to alert the system in the event of an over-current condi-
tion applied to the AAT1275 output.
The AAT1275 is available in the Pb-free, space-saving
12-pin TSOPJW and 16-pin TDFN34 packages and is
rated over the -40°C to +85°C operating temperature
range.
Boost Converter with USB Power Switch
Features
• High Frequency Boost With 5V / 500mA Output
Capability From a Single-Cell Lithium-Ion/Polymer
Battery
• Input Voltage Range: 2.7V to 5V
• V
OUT1
Adjustable or Fixed (5V)
• >90% Efficiency
• Up to 2MHz Switching Frequency
• True Load Disconnect
• Load Switch With Programmable Current Limit
• Over-Temperature, Over-Current Protection
• Inrush Current Limit
• Fault Report
• Low Shutdown Current < 1µA Typical
• -40°C to +85°C Temperature Range
• TSOPJW-12 and TDFN34-16 Packages
Applications
•
•
•
•
•
•
USB On-the-Go
Cell Phones
Digital Still Cameras
PDAs and Portable Media Players
Smart Phones
Other Hand-Held Devices
Typical Application
L1 2.2µH
LIN
SW
OUT1
V
IN
C
IN
4.7µF
10k
IN
VCC
R
FB1
432k
FB
C
OUT1
4.7µF
AAT1275
Fault
Enable
FLT
EN
OUT2
SET
R
FB2
59k
V
BUS
Output
C
OUT2
1µF
R
SET
GND
1275.2008.04.1.7
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