LM4549B AC ’97 Rev 2.1 Multi-Channel Audio Codec with Sample Rate Conversion and National 3D Sound
The LM4549B audio codec is designed for PC audio systems and complies with the AC ’97 Rev 2.1 specification. It provides full‑duplex stereo ADCs and DACs, analog mixers with independent gain, attenuation and mute controls, and supports National’s 3D Sound enhancement.
Key features include 18‑bit resolution, 90 dB ADC dynamic range, programmable sample rates from 4 kHz to 48 kHz in 1 Hz steps, extended temperature operation, and the ability to link multiple codecs via the Extended AC Link. Typical applications are desktop and portable PC audio, multi‑channel audio systems, and automotive telematics.
| Analog Mixer Dynamic Range | 97 dB (typ) |
|---|---|
| DAC Dynamic Range | 89 dB (typ) |
| ADC Dynamic Range | 90 dB (typ) |
| Sample Rate Conversion Range | 4 kHz to 48 kHz in 1 Hz steps |
| ADC/DAC Resolution | 18 Bits |
| Operating Temperature Range | -40°C to 85°C |
The ADC provides a typical dynamic range of 90 dB.