LM48410 Datasheet, PDF (1/20 Pages) National Semiconductor (TI) – Low EMI, Filterless, 2.3W Stereo Class D Audio Power Amplifier with National 3D Enhancement

July 2007
LM48410 
Low EMI, Filterless, 2.3W Stereo Class D Audio Power
Amplifier with National 3D Enhancement
General Description
The LM48410 is a single supply, high efficiency, 2.3W/chan-
nel, filterless switching audio amplifier. A low noise PWM
architecture eliminates the output filter, reducing external
component count, board area consumption, system cost, and
simplifying design. A selectable spread spectrum modulation
scheme suppresses RF emissions, further reducing the need
for output filters.
The LM48410 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
2.3W/channel of continuous output power to a 4Ω load with
less than 10% THD+N. Flexible power supply requirements
allow operation from 2.4V to 5.5V. The LM48410 offers two
logic selectable modulation schemes, fixed frequency mode,
and an EMI reducing spread spectrum mode.
The LM48410 features high efficiency compared with con-
ventional Class AB amplifiers. When driving an 8Ω speaker
from a 3.6V supply, the device operates with 85% efficiency
at P_O = 500mW/Ch. Four gain options are pin selectable
through the G0 and G1 pins. The LM48410 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 special-
ization, 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. Independent left/right shutdown controls
maximizes power savings in mixed mono/stereo applications.
Key Specifications
■ Quiescent Power Supply Current
at 3.6V supply
■ Power Output at V_DD = 5V,
R_L = 4Ω, THD ≤ 10%
■ Power Output at V_DD = 5V,
R_L = 8Ω, THD ≤ 10%
■ Shutdown current
■ Efficiency at 3.6V, 100mW into 8Ω
■ Efficiency at 3.6V, 500mW into 8Ω
■ Efficiency at 5V, 1W into 8Ω
4mA
2.3W (typ)
1.5W (typ)
0.03μA (typ)
80% (typ)
85% (typ)
86% (typ)
Features
■ ^{Selectable spread spectrum mode reduces EMI}
■ ^{Output Short Circuit Protection}
■ ^{Stereo Class D operation}
■ ^{No output filter required}
■ ^{National 3D Enhancement}
■ ^{Logic selectable gain}
■ ^{Independent channel shutdown controls}
■ ^{Minimum external components}
■ ^{Click and Pop suppression}
■ ^{Micro-power shutdown}
■ ^{Available in space-saving 4mm x 4mm LLP package}
Applications
■ ^{Mobile phones}
■ ^PDAs
■ ^Laptops
EMI Plot
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