Features 18-bit stereo DAC Multiple distinct output modes Mono speaker amplifier Stereo headphone amplifier Mono earpiece amplifier Differential mono analog input Independent loudspeaker, headphone and mono earpiece volume controls I 2C/SPI (selectable) compatible interface Ultra low shutdown current Click and Pop Suppression circuit Description The LM4937 is an integrated audio sub-system designed for mono voice, stereo music cell phones connecting to base band processors with mono differential analog voice paths. Operating on a 3.3V supply, it combines a mono speaker amplifier delivering 520mW into an 8Ω load, a stereo headphone amplifier delivering 36mW per channel into a 32Ω load, and a mono earpiece amplifier delivering 55mW into a 32Ω load. It integrates the audio amplifiers, volume control, mixer, and power management control all into a single package. In addition, the LM4937 routes and mixes the single-ended stereo and differential mono inputs into multiple distinct output modes. The LM4937 features an I 2S serial interface for full range audio and an I 2C or SPI compatible interface for control. The full range music path features an SNR of 85dB with a 192kHz playback. Boomer audio power amplifiers are designed specifically to provide high quality output power with a minimal amount of external components. Key Specification ■  POUT, BTL, 8Ω, 3.3V, 1% 520mW (typ) ■  POUT H/P, 32Ω, 3.3V, 1% 36mW (typ) ■  POUT Mono Earpiece, 32Ω, 1% 55mW (typ) ■   Shutdown current 0.6µA (typ) ■   SNR (DAC + Amplifier) 85dB (typ) Applications Cell Phones PDAs

	Block Diagram click for larger image
Typical Performance click for larger image

Parameters Values Power @ 5V 8Ohms, 1% THD 1.25 Watt Speaker THD+N 0.04 % HP THD+N 0.01 % Speaker PSRR 68 dB HP PSRR 72 dB Speaker SNR 85 dB HP SNR 85 dB Audio Mux Yes Audio Mode Control I2C, SPI Supply Range +2.7 - +5.5 V Temperature Min -40 deg C Temperature Max 85 deg C Mono Analog Inputs 2 Stereo Analog Inputs 0 Digital Audio Ports 1 Loudspeaker Type Class AB Loudspeaker Outputs 1 Headphone Type Virtual Ground AEC Q-100 Automotive Grade Undefined

Datasheets

Title		Size	Date	Other Language
	LM4937 Audio Sub-System with OCL Stereo Headphone Output and RF Suppression	1454 Kbytes	1-Nov-07

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM4937RL/NOPB RoHS Status	MICRO SMDXT	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 500 MOUSER Worldwide 250	$2.95 each at 1K+ pcs	reel of 250
LM4937TL/NOPB RoHS Status	MICRO SMD	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 0	$2.95 each at 1K+ pcs	reel of 250
LM4937TLX/NOPB RoHS Status	MICRO SMD	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 0	$2.95 each at 1K+ pcs	reel of 1000

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM4937.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM4937 is located at RoHS Status.

Part Number(s) (NSID)	Description	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM4937TLEVAL	evaluation board	Full production	Contact your distributor	$585.00 each	1

National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C1) and Banned Substances and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at: www.national.com/en/packaging/greennopb.html. Lead free products are RoHS compliant.

Lead Free product status is available through the search tool located here

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LM4937RL/NOPB	12.778 12.778	MICRO SMDXT	36	1	260	Detail	Download	N/A	XYTT I GJ3
LM4937TL/NOPB	12.998	MICRO SMD	36	1	260	Detail	Download	N/A	XYTT I GI1
LM4937TLX/NOPB	12.998	MICRO SMD	36	1	260	Detail	Download	N/A	XYTT I GI1

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM4937.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM4937 is located at RoHS Status.

Design Tools

Title	Size	Date
Audio Amplifier Digital Control Interface Evaluation Board Software

CAD Symbols and Models Download LM4937 CAD Symbols

Models N/A

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM4937RL	CMOS7	0	21301	0	0	1584000	3	449464325
LM4937TL	CMOS7	0	21301	0	0	1584000	3	449464325
LM4937TLX	CMOS7	0	21301	0	0	1584000	3	449464325

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.

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM4937.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM4937 is located at RoHS Status.