PRODUCT DATASHEET
AAT1217
SwitchRegTM
600mA, 1.2MHz, Micropower Synchronous Step-Up Converter
General Description
Features
The AAT1217 is a high efficiency, synchronous, fixed
frequency, step-up converter designed for single-cell or
dual-cell alkaline, NiMH, or NiCd battery-powered appli-
cations. The high 1.2MHz switching frequency and com-
pletely integrated control circuitry minimize the total
solution footprint area while maintaining excellent regu-
lation, ripple, and transient response throughout the full
load range.
• VIN Operation Range: 0.5V to VOUT
• VOUT Range: 2.5V to 5.5V
• 100mA Output from a Single AA Cell Input
• 400mA Output from a Dual AA Cell Input
• 500mA Output from a Single Li+ Cell Input
• High Efficiency: Up to 93% Efficiency
• Low Start-Up Voltage: 0.85V Typical
• Internal Synchronous Rectifier
▪ VOUT ≤ 4.5V: No External Schottky Diode
Fixed Frequency Pulse Width Modulation (PWM) Current-
Mode Control Scheme with Internal Compensation
Light load mode operation and low quiescent current
allow the AAT1217 to maintain high efficiency perfor-
mance for light load conditions. With a 1.2A peak induc-
tor current limit, the AAT1217 is capable of delivering
100mA to the load from a single AA cell, 400mA from
dual AA cells, or up to 500mA from a single-cell lithium-
ion battery. The AAT1217 has a 0.85V start-up voltage
with operation down to 0.5V.
•
• 1.2MHz Fixed Switching Frequency
• 1.2A Current Limit
• Light Load Mode Operation
• 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 or SOT23-6 Package
The AAT1217 is available in a Pb-free, space-saving low
profile (1mm) 6-pin TSOT23 or 6-pin SOT23 package
and is rated over the -40°C to +85°C ambient tempera-
ture range.
Applications
• 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
L1
4.7μH
SW
VIN
0.85V
SW
VOUT
VIN
0.85V
VOUT
3.3V,100mA
3.3V,100mA
VIN
VOUT
VIN
VOUT
R3
1MΩ
R3
1MΩ
COUT
4.7μF
AAT1217-1.2
R1
1.02M
COUT
4.7μF
AAT1217-3.3
CIN
4.7μF
CIN
4.7μF
FB
SHDN
FB
SHDN
R2
604k
GND
GND
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