AS1334
Datasheet - Detailed Description
8 Detailed Description
The AS1334 is a simple, step-down DC-DC converter optimized for powering portable applications that require low
dropout voltages such as mobile phones, portable communicators, and similar battery powered RFID devices. Besides
being packed with numerous features like current overload protection, thermal overload shutdown and soft start,
AS1334 displays the following characteristics:
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Its operation is based on current-mode buck architecture with synchronous rectification for high efficiency.
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Allows the application to operate at maximum efficiency over a wide range of power levels from a single Li-Ion bat-
tery cell.
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Provides for a maximum load capability of 650mA in PWM mode, wherein the maximum load range may vary
depending on input voltage, output voltage and the selected inductor.
Is ranked at an efficiency of around 96% for a 400mA load with a 3.6V input voltage.
Figure 22. AS1334 - Functional Block Diagram
PVIN
POK
VDD
1.13V
–
+
Oscillator
Current
Sense
FB
Mosfet
Control
Logic
SW
Soft Start
Main Control
EN
Shutdown
Control
AS1334
SGND
PGND
The size of the external components is reduced by using a high switching frequency (2MHz). Figure 1 on page 1
demonstrates that only three external power components are required for implementation. Also, the system controller
should set EN low during power-up and other low supply voltage conditions. See Shutdown Mode on page 12.
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