(25 PCS) LM4548VH NATIONAL SEMI IC AUDIO CIRCUIT QFP48

AC ’97 Rev 2 Codec with Sample Rate Conversion and National 3D Sound

Key Specifications n Analog Mixer Dynamic Range 97dB (typ) n D/A Dynamic Range 89dB (typ) n A/D Dynamic Range 90dB (typ) Features n AC’97 Rev2 compliant n National’s 3D Sound circuitry n High quality Sample Rate Conversion (SRC) from 4kHz to 48kHz in 1Hz increments. n Multiple Codec Support n True Line Level Output with volume control in addition to standard Line Out n Advanced power management support n Digital 3V and 5V compliant Applications n Desktop PC Audio Systems n Portable PC Systems n Mobile PC Systems

General Description The LM4548 is an audio codec for PC systems which is fully PC98 compliant and performs the analog intensive functions of the AC97 Rev2 architecture. Using 18-bit Sigma-Delta A/D’s and D/A’s, the LM4548 provides 90dB of Dynamic Range. The LM4548 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/D’s and D/A’s and an analog mixer with 4 stereo and 3 mono inputs, each of which has separate gain, attenuation and mute control. The LM4548 also provides the additional True Line-Level output and National’s 3D Sound stereo enhancement. The LM4548 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 flexibility and increased performance.