PRELIMINARY
LM49151
April 16, 2009
PRODUCT BRIEF
Mono Class D Audio Subsystem with Earpiece Driver,
Ground Referenced Headphone Amplifiers, Speaker
Protection and No Clip with Clip Control
General Description
Key Specifications
The LM49151 is a fully integrated audio subsystem designed
for portable handheld applications such as cellular phones.
The LM49151 combines a 1.25W mono E2S class D amplifier,
125mW Class AB earpiece driver, 42mW/channel stereo
ground referenced headphone drivers, volume control, input
mixer/multiplexer, and speaker protection into a single de-
vice.
■ꢀOutput power at VDD = 3.3V
ꢀꢀTHD+N ≤ 1%
LS Mode, RL = 8Ω
520mW (typ)
40mW (typ)
HP Mode, RL = 32Ω
■ꢀOutput power at VDD = 5V
ꢀꢀTHD+N ≤ 1%
LS Mode, RL = 8Ω
HP Mode, RL = 32Ω
■ꢀOutput Offset
ꢀꢀLS Mode 15
The LM49151 class D speaker amplifier features National’s
unique Automatic Level Control (ALC) that provides both a
I2C programmable no-clip feature with Clip Controls and
speaker protection. The E2S (Enhanced Emission Suppres-
sion) class D amplifier features a patented, ultra low EMI
PWM architecture that significantly reduces RF emissions
while preserving audio quality and efficiency while delivering
1.25W into an 8Ω load with <1% THD+N with a 5V supply.
The 42mW/channel headphone drivers feature National’s
ground referenced architecture that creates a ground-refer-
enced output from a single supply, eliminating the need for
bulky and expensive DC-blocking capacitors, saving space
and minimizing system cost.
1.25W (typ)
42mW (typ)
6mV (typ)
2mV (typ)
ꢀꢀHP Mode 15
Features
E2S class D amplifier
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Ground referenced outputs — eliminates output coupling
capacitors
The LM49151 features separate volume controls for the loud-
speaker and headphone inputs. Mode selection, shutdown
control, and volume are controlled through an I2C compatible
interface. The LM49151's superior click and pop suppression
eliminates audible transients on power-up/down and during
shutdown.
■
I2C programmable No Clip Function with Clip Control
Voltage limiter speaker protection
I2C volume and mode Control
Ear Piece Amplifier
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Notice: This document is not a full datasheet. For more
information regarding this product or to order samples
please contact your local National Semiconductor sales
office or visit http://www.national.com/support/dir.html
Advanced click-and-pop suppression
Low supply current
Micro-power shutdown
20-bump micro SMD package
Applications
Mobile Phones
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PDAs
Notebook PCs
Portable Electronics Devices
MP3 Players
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© 2009 National Semiconductor Corporation
300925
www.national.com