LM4937 Datasheet, PDF (1/40 Pages) Texas Instruments – Audio Sub-System with OCL Stereo Headphone Output and RF Suppression

February 2007
LM4937
Audio Sub-System with OCL Stereo Headphone Output
and RF Suppression
General 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 am-
plifier 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 ad-
dition, the LM4937 routes and mixes the single-ended stereo
and differential mono inputs into multiple distinct output
modes. The LM4937 features an I²S serial interface for full
range audio and an I²C or SPI compatible interface for control.
The full range music path features an SNR of 85dB with an
18-bit 48kHz input.
Boomer audio power amplifiers are designed specifically to
provide high quality output power with a minimal amount of
external components.
Key Specifications
■ P_OUT, BTL, 8Ω, 3.3V, 1%
■ P_OUT H/P, 32Ω, 3.3V, 1%
■ P_OUT Mono Earpiece, 32Ω, 1%
■ Shutdown current
■ SNR (DAC + Amplifier)
520mW (typ)
36mW (typ)
55mW (typ)
0.6µA (typ)
85dB (typ)
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
■ ^{I2C/SPI (selectable) compatible interface}
■ ^{Ultra low shutdown current}
■ ^{Click and Pop Suppression circuit}
Applications
■ ^{Cell Phones}
■ ^PDAs
Boomer® is a registered trademark of National Semiconductor Corporation.
© 2007 National Semiconductor Corporation 202020
www.national.com