LM49450 - I2S Input, 2.5W/Channel, Low EMI, Stereo, Class D Audio Sub-System with Ground Referenced Headphone Amplifier, 3D Enhancement, and Headphone Sense
Datasheet Packaging Samples & Pricing Reliability Knowledge Base

Features
24–Bit Stereo DAC
Stereo Filterless Class D Operation
Selectable spread spectrum mode reduces EMI
Ground Referenced Headphone Amplifiers with 100dB SNR
I 2S Compatible Audio Interface
Audio Sample Rates up to 192kHz
National’s 3D Enhancement
32-step Digital Volume Control
I 2C Compatible Control Interface
Headphone Sense Input
Stereo Analog Line Inputs
Output Short Circuit Protection
Thermal Overload Protection
Minimum external components
Click and Pop suppression
Micro-power shutdown
Available in space-saving 32 pin LLP package

Key Specification


SNR at Headphone Output 102dBA (typ)
Speaker Amplifier Efficiency  at 3.6V, 650mW/channel into 8Ω 87% (typ)
Speaker Amplifier Efficiency  at 5V, 1.1W/channel into 8Ω 80% (typ)
Quiescent Power Supply Current   Line Inputs:
Speaker Mode at LSVDD = 3.6V 7.5mA (typ)
Headphone Mode at HPVDD = 2.5V 5.3mA (typ)
Output Power/Channel  
Speaker at LSVDD = 5V:  
 RL = 4Ω, THD+N 10% 2.5W (typ)
 RL = 8Ω, THD+N 1% 1.25W (typ)
Headphone at HPVDD = 2.5V:  
 RL = 16Ω, THD+N 1% 34mW (typ)
 RL = 32Ω, THD+N 1% 36mW (typ)
PSRR at 1kHz  Speaker Mode  Headphone Mode 67dB ( typ) 77dB (typ)
Shutdown current 0.02μA (typ)

General Description


The LM49450 is a fully integrated audio subsystem designed for portable media player applications. More...


Applications


Portable Media Players
Portable Navigation Devices
Multi-Media Monitors
Laptops
Portable Gaming Devices
Mobile Handsets
  Typical Application
click for larger image


ParametersValues
Power@ 4Ohms, 10% THD 2.5 Watt
Power@ 4Ohms, 1% THD 1.9 Watt
Power@ 8Ohms, 10% THD 1.54 Watt
Power@ 8Ohms, 1% THD 1.25 Watt
THD 0.06 %
SNR 92 dB
Channels 2 Channels
THD Conditions Vdd= 3.6V, Po=300mW
SNR Conditions Vdd=3.6V, Po=500mW, f=1kHz, A-weighted
Interface I2S
Stereo Inputs Single Ended
National 3D Yes
Supply Range +2.7 - +5.5 V
Temperature Min -40 deg C
Temperature Max 85 deg C
Loudspeaker Type Class D
Headphone Type True Ground
Automotive Yes
Loudspeaker Outputs 2
D/A Channels 2


Typical Performance


*click for larger image


  Connection Diagram
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Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM49450  I 2 S Input, 2.5W/Channel, Low EMI, Stereo, Class D Audio Sub-System with Ground Referenced Headphone Amplifier, 3D Enhancement, and Headphone Sense 1131
Kbytes
26-Sep-08 Download

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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
LM49450SQLLP32NOPB1260RoHS N/A Full productionN/A
Samples
Buy Now
1K+$3.20reel
of
1000
NS
UZXYTT
L49450
12 weeksN/A
LM49450SQXLLP32NOPB1260RoHS N/A Full productionN/A
 
Buy Now
1K+$3.20reel
of
4500
NS
UZXYTT
L49450
12 weeksN/A

General Description


The LM49450 is a fully integrated audio subsystem designed for portable media player applications. The LM49450 combines a 24-bit I 2S digital-to-analog converter (DAC), 2.5W/channel stereo Class D speaker drivers, 36mW stereo ground referenced headphone drivers, volume control, and National’s unique 3D sound enhancement into a single device.

The filterless Class D amplifiers deliver 1.25W/channel into an 8Ω load with <1% THD+N with a 5V supply. The LM49450 offers two logic selectable modulation schemes, fixed frequency mode, and an EMI reducing spread spectrum mode. The 36mW/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. A headphone sense input (HPS) automatically detects the presence of a headphone, and configures the device accordingly.

The LM49450 stereo, 24-bit DAC supports a wide range of sample rates (including 192kHz, 96kHz, 48kHz, and 44.1kHz). The digital audio signal path features better than 100dB SNR, and low 0.05% THD+N when measured at the headphone outputs. The flexible 3-wire I 2S interface supports left or right justified audio data.

The LM49450 features separate 32-step volume control for the headphones and speaker outputs. 3D enhancement, mode selection, shutdown control, and volume are controlled through an I 2C compatible interface.

Output short circuit and thermal overload 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 LM49450 is available in a space saving 32-pin LLP package.

Reliability Metrics


Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM49450SQCMOS70184060010890004309006723
LM49450SQXCMOS70184060010890004309006723

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.


[Information as of 7-Nov-2009]