lm48312tlx

Manufacturer Part Numberlm48312tlx
Description2.6w, Ultra-low Emi, Filterless, Mono Class D Audio Power Amplifier With E2s
ManufacturerNational Semiconductor Corporation
lm48312tlx datasheet
 


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2.6W, Ultra-Low EMI, Filterless, Mono Class D Audio Power
Amplifier with E
2
General Description
The LM48312 is a single supply, high efficiency, mono, 2.6W,
filterless switching audio amplifier. The LM48312 features
National’s Enhanced Emissions Suppression (E
that features a unique patented ultra low EMI, spread spec-
trum, PWM architecture, that significantly reduces RF emis-
sions while preserving audio quality and efficiency. The E
system improves battery life, reduces external component
count, board area consumption, and system cost, simplifying
design.
The LM48312 is designed to meet the demands of portable
multimedia devices. Operating from a single 5V supply, the
device is capable of delivering 2.6W 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
LM48312 features both a spread spectrum modulation
scheme, and an advanced, patented edge rate control (ERC)
architecture that significantly reduces emissions, while main-
taining high quality audio reproduction (THD+N = 0.03%) and
high efficiency (η = 88%).
The LM48312 features high efficiency compared to conven-
tional Class AB amplifiers, and other low EMI Class D ampli-
fiers. When driving an 8Ω speaker from a 5V supply, the
device operates with 88% efficiency at P
LM48312 features five gain settings, selected through a sin-
gle logic input, further reducing solution size. A low power
shutdown mode reduces supply current consumption to
0.01µA.
Advanced output short circuit protection with auto-recovery
prevents the device from being damaged during fault condi-
tions. Superior click and pop suppression eliminates audible
transients on power-up/down and during shutdown.
Boomer® is a registered trademark of National Semiconductor Corporation.
© 2010 National Semiconductor Corporation
LM48312
S
Key Specifications
■ 
Efficiency at 3.6V, 400mW into 8Ω
■ 
2
S) system,
Efficiency at 5V, 1W into 8Ω
■ 
Quiescent Power Supply Current at 5V
■ 
2
S
Power Output at V
THD+N
THD+N
■ 
Power Output at V
THD+N
THD+N
■ 
Shutdown current
Features
Passes FCC Class B Radiated Emissions with 20 inches
of cable
E
2
S System Reduces EMI while Preserving Audio Quality
and Efficiency
Output Short Circuit Protection with Auto-Recovery
No output filter required
= 1W. The
O
Improved Audio Quality
Minimum external components
Five Logic Selectable Gain Settings (0, 3, 6, 9, 12dB)
Low Power Shutdown Mode
Click and Pop suppression
Available in space-saving microSMD package
Applications
Mobile phones
PDAs
Laptops
301107
March 19, 2010
= 4Ω
= 5V, R
DD
L
10%
1%
= 8Ω
= 5V, R
DD
L
10%
1%
www.national.com
84% (typ)
88% (typ)
3.1mA
2.6W (typ)
2.1W (typ)
1.6W (typ)
1.3W (typ)
0.01μA (typ)