600mA, 1.2MHz, Micropower
Synchronous Step-Up Converter
General Description
Features
AAT1217
SwitchReg
™
The AAT1217 a high efficiency, synchronous, fixed
frequency, step-up converter designed for single-
cell or dual-cell alkaline, NiMH, or NiCd battery-
powered applications. The high 1.2MHz switching
frequency and completely integrated control cir-
cuitry minimize the total solution footprint area
while maintaining excellent regulation, ripple, and
transient response throughout the full load range.
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The AAT1217 is available in a Pb-free, space-sav-
ing low profile (1mm) 6-pin TSOT23 package and
is rated over the -40°C to +85°C ambient tempera-
ture range.
Pulse skipping mode operation and low quiescent
current allow the AAT1217 to maintain high effi-
ciency performance for light load and sleep mode
conditions. With a 1.2A peak switch current limit,
the AAT1217 is capable of delivering 100mA to the
load from a single AA cell or up to 400mA from dual
AA cells. The AAT1217 has a 0.85V start-up volt-
age with operation down to 0.5V.
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V
IN
Operation Range: 0.5V to V
OUT
V
OUT
Range: 2.5V to 5.5V
100mA Output from a Single AA Cell Input
400mA Output from a Dual AA Cell Input
High Efficiency: Up to 93% Efficiency
Low Start-Up Voltage: 0.85V Typical
Internal Synchronous Rectifier
— V
OUT
≤ 4.5V: No External Schottky Diode
Fixed Frequency Pulse Width Modulation
(PWM) Current-Mode Control Scheme with
Internal Compensation
1.2MHz Fixed Switching Frequency
1.2A Current Limit
Light Load Pulse Skipping Mode Operation
Low 80µA No Load Input Current
Over-Current Protection
EMI Reduction Anti-Ringing Control Circuitry
Low Shutdown Current: <1.0µA
-40°C to +85°C Ambient Temperature Range
Low Profile (1mm) TSOT23-6 Package
Applications
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Cellular and Smart Phones
Digital Still and Video Cameras
Microprocessors and DSP Core Supplies
MP3 Player
Portable Instruments
Wireless and DSL Modems
Typical Application
L1
4.7µH
SW
L1
4.7µH
SW
V
IN
: 0.85V
C
IN
4.7µF
R3
1MΩ
VIN
SHDN
AAT1217-1.2
GND
VOUT
FB
V
OUT
:
3.3V,100 mA
R1
1.02MΩ
R2
604kΩ
C
OUT
4.7µF
V
IN
: 0.85V
C
IN
4.7µF
R3
1MΩ
VIN
SHDN
AAT1217-3.3
GND
VOUT
FB
V
OUT
:
3.3V,100 mA
C
OUT
4.7µF
1217.2007.07.1.0
1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
