LM49370 - Boomer Audio Power Amplifier Series Audio Sub-System with an Ultra Low EMI, Spread Spectrum, Class D Loudspeaker Amplifier, a Dual-Mode Stereo Headphone Amplifier, and a Dedicated Interface for Bluetooth Transceivers

LM49370 - Boomer Audio Power Amplifier Series Audio Sub-System with an Ultra Low EMI, Spread Spectrum, Class D Loudspeaker Amplifier, a Dual-Mode Stereo Headphone Amplifier, and a Dedicated Interface for Bluetooth Transceivers from the PowerWise® Family

Datasheet	Packaging	Samples & Pricing	Eval. Boards	Reliability	Design Tools	Knowledge Base

Features

•	Spread Spectrum Class D architecture reduces EMI
•	Mono Class D 8Ω amplifier, 490 mW at 3.3V
•	OCL or AC-coupled headphone operation
•	33mW stereo headphone amplifier at 3.3V
•	115 mW earpiece amplifier at 3.3V
•	18-bit stereo DAC
•	16-bit mono ADC
•	8 kHz to 192 kHz stereo audio playback
•	8 kHz to 48 kHz mono recording
•	Bidirectional I 2S compatible audio interface
•	Bidirectional PCM compatible audio interface for Bluetooth transceivers
•	I 2S-PCM Bridge with sample rate conversion
•	Sigma-Delta PLL for operation from any clock at any sample rate
•	Digital 3D Stereo Enhancement
•	FIR filter programmability for simple tone control
•	Low power clock network operation if a 12 MHz or 13 MHz system clock is available
•	Read/write I 2C or SPI compatible control interface
•	Automatic headphone & microphone detection
•	Support for internal and external microphones
•	Automatic gain control for microphone input
•	Differential audio I/O for external cellphone module
•	Mono differential auxiliary output
•	Stereo auxiliary inputs
•	Differential microphone input for internal microphone
•	Flexible audio routing from input to output
•	32 Step volume control for mixers in 1.5 dB steps
•	16 Step volume control for microphone in 2 dB steps
•	Programmable sidetone attenuation in 3 dB steps
•	Two configurable GPIO ports
•	Multi-function IRQ output
•	Micro-power shutdown mode
•	Available in the 4 x 4 mm 49 bump micro SMDxt package

Key Specification

P_{HP (AC-COUP)} (A_V_DD = 3.3V, 32Ω, 1% THD)	33 mW
P_{HP (OCL)} (A_V_DD = 3.3V, 32Ω, 1% THD)	31 mW
P_LS ( LS_V_DD = 5V, 8Ω, 1% THD)	1.2 W

P_LS (LS_V_DD = 4.2V, 8Ω, 1% THD)	900 mW
P_LS (LS_V_DD = 3.3V, 8Ω, 1% THD)	490 mW

Shutdown Current	0.8 µA
PSRR_LS (217 Hz, LS_V_DD = 3.3V)	70 dB
SNR_LS (AUX IN to Loudspeaker)	90 dB (typ)
SNR_DAC (Stereo DAC to AUXOUT)	85 dB (typ)
SNR_ADC (Mono ADC from Cell Phone In)	90 dB (typ)
SNR_HP (Aux In to Headphones)	98 dB (typ)

General Description

The LM49370 is an integrated audio subsystem that supports both analog and digital audio functions. More...

Applications

•	Smart phones
•	Mobile Phones and Multimedia Terminals
•	PDAs, Internet Appliances and Portable Gaming
•	Portable DVD/CD/AAC/MP3 Players
•	Digital Cameras/Camcorders

Typical Application

*click for larger image

Parameters Values

Power@ 8Ohms, 1% THD 1.2 Watt

THD 0.04 %

PSRR 70 dB

SNR 90 dB

THD Conditions 8ohm; Vdd=3.3; Po=400mW

PSRR Conditions Vrip=200mVp-p; f=217Hz

User Supply 5 Volt

Audio Mux Yes

Capless Headphone Yes

ClassD Driver Yes

Interface I2C I2S SPI PCM

Stereo Inputs I2S

National 3D Yes

Digital Volume Control Max 12 dB

Digital Volume Control Min -46.5 dB

Supply Range +2.0 - +5.5 V

Mono Inputs PCM

Temperature Min -40 deg C

Temperature Max 85 deg C

Loudspeaker Type Class D

Headphone Type Virtual Ground

Loudspeaker Outputs 3

PowerWise Yes

A/D Channels 1 Channels

D/A Channels 2

Typical Performance

click for larger image

Also Recommended

LM49352▲

Lower Power Cusumption Headphone, Higher Output Power

Additional Resources

Design Tools

Block Diagram

*click for larger image

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM49370 Audio Sub-System with an Ultra Low EMI, Spread Spectrum, Class D Loudspeaker Amplifier, a Dual-Mode Stereo Headphone Amplifier, and a Dedicated PCM Interface for Bluetooth Transceivers	2752 Kbytes	12-Feb-08	Download

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Package Availability, Models, Samples & Pricing

Part Number

Package

Factory Lead Time

Models

Samples &
Electronic
Orders

Budgetary Pricing

Std
Pack
Size

Package
Marking
Format

Type

Pins

Spec.

MSL
Rating

Peak
Reflow

RoHS
Report

CAD
Symbols

Weeks

Qty

$US each

LM49370RLEVAL

LM49370RLEVAL Evaluation Board

Full production

N/A

$585.00

N/A

LM49370RL

MICRO SMDXT

NOPB

260

RoHS

N/A

Full production

N/A

1K+

$3.95

reel
of
250

XYTT
I GI3

6 weeks

N/A

LM49370RLX

MICRO SMDXT

NOPB

260

RoHS

N/A

Full production

N/A

1K+

$3.95

reel
of
1000

XYTT
I GI3

6 weeks

N/A

General Description

The LM49370 is an integrated audio subsystem that supports both analog and digital audio functions. The LM49370 includes a high quality stereo DAC, a mono ADC, a stereo headphone amplifier, which supports output cap-less (OCL) or AC-coupled (SE) modes of operation, a mono earpiece amplifier, and an ultra-low EMI spread spectrum Class D loudspeaker amplifier. It is designed for demanding applications in mobile phones and other portable devices.

The LM49370 features a bi-directional I 2S interface and a bi-directional PCM interface for full range audio on either interface. The LM49370 utilizes an I 2C or SPI compatible interface for control. The stereo DAC path features an SNR of 85 dB with an 18-bit 48 kHz input. In SE mode the headphone amplifier delivers at least 33 mW_RMS to a 32Ω single-ended stereo load with less than 1% distortion (THD+N) when A_V_DD = 3.3V. The mono earpiece amplifier delivers at least 115mW_RMS to a 32Ω bridged-tied load with less than 1% distortion (THD+N) when A_V_DD = 3.3V. The mono speaker amplifier delivers up to 490mW into an 8Ω load with less than 1% distortion when LS_V_DD = 3.3V and up to 1.2W when LS_V_DD = 5.0V.

The LM49370 employs advanced techniques to reduce power consumption, to reduce controller overhead, to speed development time, and to eliminate click and pop. Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components. It is therefore ideally suited for mobile phone and other low voltage applications where minimal power consumption, PCB area and cost are primary requirements.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM49370RL	CMOS7	0	18406	0	0	1089000	4	309006723
LM49370RLX	CMOS7	0	18406	0	0	1089000	4	309006723

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

Title	Size in Kbytes	Date
Audio Amplifier Digital Control Interface Evaluation Board Software			View

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Application Notes

Title	Size in Kbytes	Date
AN-1609: Application Note 1609 LM49370 Demonstration Board Guide	4417 Kbytes	9-May-07	Download
AN-1609 (Chinese): Application Note 1609 LM49370 Demonstration Board Guide	1134 Kbytes
AN-1591: Application Note 1591 The LM49370 PCM/I 2 S Bridge	737 Kbytes	17-Jul-07	Download
AN-1591 (Chinese): Application Note 1591 The LM49370 PCM/I 2 S Bridge	546 Kbytes

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[Information as of 7-Nov-2009]