LM4949 - Stereo Class D Audio Subsystem with OCL Headphone Amplifier
Datasheet Packaging Samples & Pricing Eval. Boards Reliability Design Tools Application Notes Knowledge Base

Features
• Output Short Circuit Protection
• Thermal Shutdown
• Stereo filterless Class D operation
• Selectable OCL/CC Headphone Drivers
• RF Suppression
• I 2C Control Interface
• 32-step digital volume control
• Independent Speaker and Headphone Gain Settings
• Minimum external components
• Click and Pop suppression
• Micro-power shutdown
• Available in space-saving 25 bump µSMD package

Key Specification

■  Efficiency VDD = 3.6V, 400mW  into 8Ω 86.5%
■  Efficiency VDD = 5V, 1W into 8Ω 87.4%
■  Quiescent Power Supply Current   @ 3.6V 9.36mA
■  Power Output at VDD = 5V  
 Speaker:   RL = 4Ω, THD+N ≤ 1%   RL = 8Ω, THD+N ≤ 1%   RL = 4Ω, THD+N ≤ 10% 2W 1.19W 2.5W
 Headphone:   RL = 16Ω, THD+N ≤ 1%   RL = 32Ω, THD+N ≤ 1% 153mW 89mW
■  Shutdown Current 0.1μA

General Description

The LM4949 is a fully integrated audio subsystem designed for stereo cell phone applications. More...


Applications

• Mobile phones
• PDAs
• Laptops
  Typical Application
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ParametersValues
Power@ 4Ohms, 10% THD 1.24 Watt
Power@ 4Ohms, 1% THD 1 Watt
Power@ 8Ohms, 10% THD 0.765 Watt
Power@ 8Ohms, 1% THD 0.615 Watt
THD 0.02 %
PSRR 73 dB
SNR Undefined dB
Channels 5 Channels
THD Conditions RL=8ohms, Po=300mW
PSRR Conditions Differential Input Mode, f=217Hz
SNR Conditions Undefined
User Supply 3.6 Volt
Audio Mux Yes
Capless Headphone Yes
ClassD Driver Yes
Interface I2C
Stereo Inputs 1,2
National 3D No
Digital Volume Control Max 18 dB
Digital Volume Control Min -59 dB
Output Modes 100
Supply Range +2.7 - +5.5 V
Mono Inputs 1
Temperature Min -40 deg C
Temperature Max 85 deg C
Loudspeaker Type Class D
Headphone Type Virtual Ground
Loudspeaker Outputs 2


Typical Performance

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  Additional Resources
Design Tools

Application Notes


Connection Diagram

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Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM4949  Stereo Class D Audio Subsystem with OCL Headphone Amplifier 984
Kbytes		 13-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
LM4949TLEVALStereo Class D Audio Subsystem with OCL Headphone AmplifierFull productionN/A
 
Buy Now 		1+$325.001-
N/AN/A
LM4949TLMICRO SMD25NOPB1260RoHS Download Full productionN/A
Samples
Buy Now 		1K+$2.40reel
of
250		XYTT
I GH3
6 weeksN/A
LM4949TLXMICRO SMD25NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$2.40reel
of
3000		XYTT
I GH3
6 weeksN/A

General Description

The LM4949 is a fully integrated audio subsystem designed for stereo cell phone applications. The LM4949 combines a 2.5W stereo Class D amplifier plus a separate 190mW stereo headphone amplifier, volume control, and input mixer into a single device. The filterless class D amplifiers deliver 1.19W/channel into an 8Ω load with <1% THD+N from 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. Additionally, the headphone amplifiers can be configured with capacitively coupled (CC)loads, or used to drive an external headphone amplifier. When configured for an external amplifier, the VDD/2 output (VOC) controls the external amplifier’s shutdown input.

For improved noise immunity, the LM4949 features fully differential left, right and mono inputs. The three inputs can be mixed/multiplexed to either the speaker or headphone amplifiers. The left and right inputs can be used as separate single-ended inputs, mixing multiple stereo audio sources. The mixer, volume control, and device mode select 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.

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM4949TLCMOS70184060010890004309006723
LM4949TLXCMOS70184060010890004309006723

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.


Design Tools

TitleSize in Kbytes Date Click link below to Download    
Audio Amplifier Digital Control Interface Evaluation Board Software     View    

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Application Notes

TitleSize in Kbytes Date Click link below to Download
AN-1567: Application Note 1567 LM4949 Demonstration Board 3533
Kbytes		 18-Jul-07 Download
AN-1567 (Chinese): Application Note 1567 LM4949 Demonstration Board
 1008 Kbytes  

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More Application Notes

TitleSize in Kbytes Date Click link below to Download
AN-1496: Application Note 1496 Noise, TDMA Noise, and Suppression Techniques 85
Kbytes		 28-Apr-08 Download
AN-1496 (Chinese): Application Note 1496 Noise, TDMA Noise, and Suppression Techniques
 407 Kbytes  

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[Information as of 8-Nov-2009]