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Features
E
2S system reduces EMI preserving audio quality and efficiency
Output Short Circuit Protection
Stereo Class D operation
No output filter required
National 3D Enhancement
Minimum external components
Click and Pop suppression
Micro-power shutdown
Available in space-saving approximately 2mm x 2.2mm micro SMD package
Description The LM48413 is a single supply, high efficiency, 1.2W/channel, filterless switching audio amplifier. The LM48413 features
National’s Enhanced Emissions Suppression (E
2S) system - a unique patented ultra low EMI, spread spectrum, PWM architecture. It significantly reduces RF emission while
preserving audio quality and efficiency. The E
2S system improves battery life, reduces external component count, board area consumption, system cost and product design cycle
time. The LM48413TL is available in a micro-SMD package, further saving space.
The LM48413 is designed to meet the demands of mobile phones and other portable communication devices. Operating from a single
5V supply, the device is capable of delivering 1.2W/channel of continuous output power to a 8Ω load with less than 1% THD+N.
Flexible power supply requirements allow operation from 2.4V to 5.5V. The wide band spread spectrum architecture of the LM48413
reduces EMI-radiated emissions due to the modulator frequency.
The LM48413 features high efficiency compared with conventional Class AB amplifiers. The E
2S system includes an advanced, patent-pending edge rate control (ERC) architecture that further reduce emissions by minimizing
the high frequency components of the device output, while maintaining its high quality audio reproduction and high efficiency
(η = 85% at VDD = 3.6V, PO = 500mW). The LM48413 also includes National’s 3D audio enhancement that improves stereo sound quality. In devices where
the left and right speakers are in close proximity, 3D enhancement affects channel specialization, widening the perceived
soundstage.
Output short circuit protection prevents the device from being damaged during fault conditions. Superior click and pop suppression
eliminates audible transients on power up/down and during shutdown. Shutdown control also provided to maximizes power savings.
Key Specification
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Quiescent Power Supply Current
at 3.6V supply
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4mA (typ)
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Power Output at VDD = 5V,
RL = 8Ω, THD
≤ 1%
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1.2W (typ)
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Shutdown current
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0.03μA (typ)
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Efficiency at 3.6V, 100mW into 8Ω
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80% (typ)
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Efficiency at 3.6V, 500mW into 8Ω
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85% (typ)
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Efficiency at 5V, 1W into 8Ω
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86% (typ)
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Applications
Mobile phones
PDAs
Laptops
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