LM48411
Ultra-Low EMI, Filterless, 2.5W, Stereo, Class D Audio
Power Amplifier with E2S
LM48411 Ultra-Low EMI, Filterless, 2.5W, Stereo, Class D Audio Power Amplifier with E
General Description
The LM48411 is a single supply, high efficiency, 2.5W/channel Class D audio amplifier. The LM48411 features National's
Enhanced Emissions Suppression (E2S) system, that features a unique patent-pending ultra low EMI, spread spectrum, PWM architecture, that significantly reduces RF emissions 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. Operating 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 allow 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 conventional Class AB amplifier. The E2S system includes an
advanced, patent-pending edge rate control (ERC) architecture 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 VDD = 3.6V, PO = 500mW). Four gain options are pin selectable 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 suppression 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
speaker87% (typ)
■ Efficiency at 3.6V, 100mW into 8Ω
speaker80% (typ)
■ Efficiency at 5V, 1W into 8Ω
speaker88% (typ)
■ Quiescent current, 3.6V supply4.2mA (typ)
■ Power Output at V
RL = 4Ω, THD ≤ 10%
■ Power Output at V
RL = 8Ω, THD ≤ 10%
■ Total shutdown power supply
current
■ Single supply range
DD
DD
= 5V
2.5W (typ)
= 5V
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
■
Boomer® is a registered trademark of National Semiconductor Corporation.
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (Note 1)6.0V
Storage Temperature−65°C to +150°C
Voltage at Any Input Pin
Power Dissipation (Note 3)Internally Limited
ESD Rating, all other pins (Note 4)2.0kV
ESD Rating (Note 5)200V
Junction Temperature (T
VDD + 0.3V ≥ V ≥ GND - 0.3V
)
JMAX
150°C
Thermal Resistance
θJA (micro SMD)
Soldering Information
See AN-1112 "microSMD Wafers Level Chip Scale
Package."
Operating Ratings (Notes 1, 2)
Temperature Range
T
≤ TA ≤ T
MIN
Supply Voltage
Electrical Characteristics The following specifications apply for A
otherwise specified. Limits apply for TA = 25°C. VDD = 3.6V.