LM48413 Datasheet, PDF (1/22 Pages) National Semiconductor (TI) – Ultra Low EMI, Filterless, 1.2W Stereo Class D Audio Power Amplifier with E2S and National 3D Enhancement

January 9, 2009
LM48413 
Ultra Low EMI, Filterless, 1.2W Stereo Class D Audio Power
Amplifier with E²S and National 3D Enhancement
General Description
The LM48413 is a single supply, high efficiency, 1.2W/chan-
nel, filterless switching audio amplifier. The LM48413 fea-
tures National’s Enhanced Emissions Suppression (E²S)
system - a unique patented ultra low EMI, spread spectrum,
PWM architecture. It significantly reduces RF emission while
preserving audio quality and efficiency. The E²S system im-
proves 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. Operat-
ing 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 al-
low 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 con-
ventional Class AB amplifiers. The E²S system includes an
advanced, patent-pending edge rate control (ERC) architec-
ture that further reduce emissions by minimizing the high
frequency components of the device output, while maintain-
ing its high quality audio reproduction and high efficiency (η
= 85% at V_DD = 3.6V, P_O = 500mW). The LM48413 also in-
cludes 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 sup-
pression eliminates audible transients on power up/down and
during shutdown. Shutdown control also provided to maxi-
mizes power savings.
Key Specifications
■ Quiescent Power Supply Current
at 3.6V supply
■ Power Output at V_DD = 5V,
R_L = 8Ω, THD ≤ 1%
■ Shutdown current
■ Efficiency at 3.6V, 100mW into 8Ω
■ Efficiency at 3.6V, 500mW into 8Ω
■ Efficiency at 5V, 1W into 8Ω
4mA (typ)
1.2W (typ)
0.03μA (typ)
80% (typ)
85% (typ)
86% (typ)
Features
■ ^{E2S 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
Applications
■ ^{Mobile phones}
■ ^PDAs
■ ^Laptops
EMI Plot Using 6 inch Speaker Cables
EMI Radiation vs Frequency
V_DD = 3V, R_L = 15μH + 8Ω + 15μH
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