Features
| • | E
2S class D amplifier
|
| • | Ground referenced outputs — eliminates output coupling capacitors |
| • | I
2C programmable No Clip Function with Clip Control
|
| • | Voltage limiter speaker protection |
| • | I
2C volume and mode Control
|
| • | Ear Piece Amplifier |
| • | Advanced click-and-pop suppression |
| • | Low supply current |
| • | Micro-power shutdown |
| • | 20-bump micro SMD package |
Description The LM49151 is a fully integrated audio subsystem designed for portable handheld applications such as cellular phones. The
LM49151 combines a 1.25W mono E
2S 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 device.
The LM49151 class D speaker amplifier features National’s unique Automatic Level Control (ALC) that provides both a I
2C programmable no-clip feature with Clip Controls and speaker protection. The E
2S (Enhanced Emission Suppression) 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-referenced
output from a single supply, eliminating the need for bulky and expensive DC-blocking capacitors, saving space and minimizing
system cost.
The LM49151 features separate volume controls for the loudspeaker and headphone inputs. Mode selection, shutdown control,
and volume are controlled through an I
2C compatible interface. The LM49151's superior click and pop suppression eliminates audible transients on power-up/down and
during shutdown.
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
Key Specification
| ■
Output power at VDD = 3.3V
THD+N
≤ 1%
|
|
| LS Mode, RL = 8Ω
|
520mW (typ)
|
| HP Mode, RL = 32Ω
|
40mW (typ)
|
| ■
Output power at VDD = 5V
THD+N
≤ 1%
|
|
| LS Mode, RL = 8Ω
|
1.25W (typ)
|
| HP Mode, RL = 32Ω
|
42mW (typ)
|
| ■
Output Offset
|
|
|
LS Mode 15
|
6mV (typ)
|
|
HP Mode 15
|
2mV (typ)
|
Applications
| • | Mobile Phones |
| • | PDAs |
| • | Notebook PCs |
| • | Portable Electronics Devices |
| • | MP3 Players |
|
|
