Ac \\\'97 Rev 2 Codec With Sample Rate Conversion And National 3d Sound - National Semiconductor

The LM4546 is an Audio CODEC for PC systems which is fully PC98 compliant and performs the Analog intensive functions of the AC97 Rev 2 architecture. Using 18-bit Sigma-Delta A/Ds and D/As, the LM4546 provides 90dB of Dynamic Range. The LM4546 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 A/Ds and D/As and an Analog mixer with 2 stereo and 3 mono inputs, each of which has separate gain, attenuation and mute control. The LM4546 also provides Nationals 3D Sound stereo en- hancement. The LM4546 supports variable sample rate conversion as defined in the AC97 Rev2 specification. The sample rate for the A/D and D/A CAN be programmed separately to convert any rate between 4kHz - 48kHz with a resolution of 1Hz. The AC97 architecture separates the Analog and digital functions of the PC Audio system allowing both for system design flex- ibility and increased performance. By National Semiconductor Corporation