LM48411 Datasheet, PDF (1/18 Pages) National Semiconductor (TI) – Ultra-Low EMI, Filterless, 2.5W, Stereo, Class D Audio Power Amplifier with E2S

October 2007
LM48411 
Ultra-Low EMI, Filterless, 2.5W, Stereo, Class D Audio
Power Amplifier with E²S
General Description
The LM48411 is a single supply, high efficiency, 2.5W/chan-
nel Class D audio amplifier. The LM48411 features National's
Enhanced Emissions Suppression (E²S) system, that fea-
tures a unique patent-pending ultra low EMI, spread spec-
trum, PWM architecture, that significantly reduces RF emis-
sions while preserving audio quality and efficiency. The E²S
system improves battery life, reduces external component
count, board area consumption, system cost, and simplifying
design.
The LM48411 is designed to meet the demands of mobile
phones and other portable communication devices. Operat-
ing on a single 5V supply, it is capable of delivering 2.5W/
channel of continuous output power to a 4Ω load with less
than 10% THD+N. Its flexible power supply requirements al-
low operation from 2.4V to 5.5V. The wide band spread
spectrum architecture of the LM48411 reduces EMI-radiated
emissions due to the modulator frequency.
The LM48411 features high efficiency compared to a con-
ventional Class AB amplifier. The E²S system includes an
advanced, patent-pending edge rate control (ERC) architec-
ture that further reduce emissions by minimizing the high
frequency component of the device output, while maintaining
high quality audio reproduction and high efficiency (η = 87%
at V_DD = 3.6V, P_O = 500mW). Four gain options are pin se-
lectable through GAIN0 and GAIN1 pins.
The LM48411 features a low-power consumption shutdown
mode. Shutdown may be enabled by driving the Shutdown
pin to a logic low (GND).
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 control
maximizes power savings in mixed mono/stereo applications.
Key Specifications
■ Efficiency at 3.6V, 500mW into 8Ω
speaker
■ Efficiency at 3.6V, 100mW into 8Ω
speaker
■ Efficiency at 5V, 1W into 8Ω
speaker
■ Quiescent current, 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%
■ Total shutdown power supply
current
■ Single supply range
87% (typ)
80% (typ)
88% (typ)
4.2mA (typ)
2.5W (typ)
1.5W (typ)
0.01µA (typ)
2.4V to 5.5V
Features
■ ^{E2S system reduces EMI preserving Audio Quality and}
Efficiency
■ ^{Output short circuit protection}
■ ^{Stereo Class D Operation}
■ ^{No output filter required for inductive loads}
■ ^{Logic selectable gain}
■ ^{Independent shutdown control}
■ ^{Minimum external components}
■ ^{"Click and pop" suppression circuitry}
■ ^{Micro-power shutdown mode}
■ ^{Available in space-saving 0.5mm pitch micro SMD}
package
Applications
■ ^{Mobile phones}
■ ^PDAs
■ ^{Portable electronic devices}
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