LM4548

Supply Voltage ....................6.0V
Storage Temperature ....... −65°C to +150°C
Input Voltage ..........  −0.3V to VDD +0.3V
ESD Susceptibility (Note 5) ..........   2500V
pins 27, 28....................   1500V
pin 3.........................  750V
ESD Susceptibility (Note 6) ...........  200V
pin 3 ......................... 100V
Junction Temperature ..............150°C
Soldering Information
TQFP Package
Vapor Phase (60 sec.) ..............215°C
Infrared (15 sec.) .................220°C
See AN-450 ²Surface Mounting and their Effects on
Product Reliability² for other methods of
soldering surface mount devices.
_JA (typ)-VBH48A ............... 74°C/W

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.