LM49270 - Filterless 2.2W Class D Audio Subsystem with OCL Headphone Amplifier, 3D Enhancement, and Headphone Sense
Datasheet Packaging Samples & Pricing Eval. Boards Knowledge Base

Features
Stereo filterless Class D amplifier
Selectable OCL/CC headphone amplifier
Headphone sense ability
National’s 3D Enhancement
RF suppression
I 2C control interface
32-step digital volume control
6 Operating Modes
Output short circuit protection and thermal shutdown protection
Minimum external components
Click and Pop suppression
Micro-power shutdown
Independent speaker and headphone volume controls
Available in space-saving 28 pin LLP package

Key Specification


Stereo Class D Amplifier Efficiency:  
VDD = 3.3V, 450mW/Ch into 8Ω 84%
VDD = 5V, 1W/Ch into 8Ω 84%
Quiescent Power Supply Current, VDD = 3.3V
Speaker Mode 5.5mA
Headphone Mode (OCL) 4mA
Power Output/Channel, VDD = 5V  
Class D Speaker amplifier:  
 RL = 4Ω, THD+N = 10% 2.2W
 RL = 8Ω, THD+N = 1% 1.06W
Headphone amplifier:  
 RL = 16Ω, THD+N = 1% 155mW
 RL = 32Ω, THD+N = 1% 90mW
Shutdown current 0.02μA

General Description


The LM49270 is a fully integrated audio subsystem designed for stereo multimedia applications. More...


Applications


Portable DVD players
Smart phones
PDAs
Laptops
  Typical Application
click for larger image


ParametersValues
Power@ 4Ohms, 10% THD 0.87 Watt
Power@ 4Ohms, 1% THD 0.7 Watt
Power@ 8Ohms, 10% THD 0.56 Watt
Power@ 8Ohms, 1% THD 0.45 Watt
THD 0.02 %
PSRR 75 dB
SNR Undefined dB
Channels 4 Channels
THD Conditions Pout = 12mW, RL=32ohm, OCL mode
PSRR Conditions f=217Hz, Vripple = 200mVpp, HP OCL mode
SNR Conditions Undefined
User Supply 3.3 Volt
Audio Mux Yes
Capless Headphone Yes
ClassD Driver Yes
Interface I2C
Stereo Inputs 1
National 3D Yes
Digital Volume Control Max 18 dB
Digital Volume Control Min -59 dB
Output Modes 6
Supply Range +2.4 - +5.5 V
Mono Inputs 0
Temperature Min -40 deg C
Temperature Max 85 deg C
Loudspeaker Type Class D
Headphone Type Virtual Ground
Loudspeaker Outputs 2


Typical Performance


click for larger image


  Connection Diagram
click for larger image



Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM49270  Filterless 2.2W Stereo Class D Audio Subsystem with OCL Headphone Amplifier, 3D Enhancement, and Headphone Sense 2575
Kbytes
17-Mar-07 Download

If you have trouble printing or viewing PDF file(s), see Printing Problems.


Package Availability, Models, Samples & Pricing
Part NumberPackageFactory Lead TimeModelsSamples &
Electronic
Orders
Budgetary PricingStd
Pack
Size
Package
Marking
Format
TypePinsSpec.MSL
Rating
Peak
Reflow
RoHS
Report
CAD
Symbols
WeeksQtyQty$US each
LM49270SQEVALLM49270SQEVAL Evaluation BoardPreliminaryN/A
 
Buy Now
 CALLN/A-
N/AN/A
LM49270SQELLP28NOPB1260RoHS N/A Full productionN/A
 
Buy Now
1K+$2.45reel
of
250
NS
UZXYTT
49270SQ
6 weeksN/A
LM49270SQLLP28NOPB1260RoHS N/A Full productionN/A
Samples
Buy Now
1K+$2.45reel
of
1000
NS
UZXYTT
49270SQ
6 weeksN/A
LM49270SQXLLP28NOPB1260RoHS N/A Full productionN/A
 
Buy Now
1K+$2.45reel
of
4500
NS
UZXYTT
49270SQ
6 weeksN/A

General Description


The LM49270 is a fully integrated audio subsystem designed for stereo multimedia applications. The LM49270 combines a 2.2W stereo Class D amplifier with a 155mW stereo headphone amplifier, volume control, headphone sense, and National’s unique 3D sound enhancement into a single device. The LM49270 uses flexible I 2C control interface for multiple application requirements.

The filterless stereo class D amplifiers delivers 2.2W/channel into a 4Ω load with less than 10% THD+N with a 5V supply. The headphone amplifier features National’s Output Capacitor-less (OCL) architecture that eliminates the output coupling capacitors required by traditional headphone amplifiers.

The IC features a headphone sense input (HPS) that automatically detects the presence of a headphone and configures the device accordingly. The LM49270 can automatically switch from OCL headphone output to a line driver output. If the VOC pin is pulled to GND, the VOC amplifier is disabled and the VOC pin is internally set to GND. This feature allows the LM49270 to be used as a line driver in OCL mode without a GND conflict on the headphone jack sleeve. Additionally, the headphone amplifier can be configured as capacitively coupled (CC).

The LM49270 features a 32 step volume control for the headphone and stereo outputs. The device mode select and volume are controlled through an I 2C compatible interface.

Output short circuit and thermal shutdown protection prevent the device from being damaged during fault conditions. Superior click and pop suppression eliminates audible transients on power-up/down and during shutdown. The LM49270 is available in a space saving 28-pin, 5x5mm LLP package.

Application Notes


TitleSize in Kbytes Date Click link below to Download
AN-1638: Application Note 1638 LM49270 Demonstration Board 321
Kbytes
24-May-07 Download
AN-1638 (Chinese): Application Note 1638 LM49270 Demonstration Board
550 Kbytes  

If you have trouble printing or viewing PDF file(s), see Printing Problems.

[Information as of 7-Nov-2009]