LM4549B

LM4549B AC ’97 Rev 2.1 Multi-Channel Audio Codec with Sample Rate Conversion and National 3D Sound September 2006 LM4549B AC ’97 Rev 2.1 Multi-Channel Audio Codec with Sample Rate Conversion and National 3D Sound General Description The LM4549B is an audio codec for PC systems which is fully PC99 compliant and performs the analog intensive functions of the AC ’97 Rev 2.1 architecture. Using 18-bit Sigma-Delta ADCs and DACs, the LM4549B provides 90 dB of Dynamic Range. The LM4549B was designed specifically to provide a high quality audio path and provide all analog functionality in a PC audio system. It features full duplex stereo ADCs and DACs and analog mixers with access to 4 stereo and 4 mono inputs. Each mixer input has separate gain, attenuation and mute control and the mixers drive 1 mono and 2 stereo outputs, each with attenuation and mute control. The LM4549B supports National’s 3D Sound stereo enhancement and a comprehensive sample rate conversion capability. The sample rate for the ADCs and DACs can be programmed separately with a resolution of 1 Hz to convert any rate in the range 4 kHz – 48 kHz. Sample timing from the ADCs and sample request timing for the DACs are completely deterministic to ease task scheduling and application software development. These features together with an extended temperature range also make the LM4549B suitable for non-PC codec applications. The LM4549B features the ability to connect several codecs together using the Extended AC Link...