What is the LM4549BVH?
The LM4549BVH is a Texas Instruments Audio, AC '97 codec (cite:). It integrates two ADCs and two DACs at 18-bit resolution (cite:,), delivering a typical dynamic range of 90 dB on the ADC side and 89 dB on the DAC side (cite:). The serial data interface (cite:) and sigma-delta architecture (cite:) are standard for AC '97 compliance.
The 0.50 mm pitch on the LQFP demands a controlled reflow profile; check the MSL before the oven to avoid popcorning.
Supply rails and power sequencing
The analog supply range is 4.2V to 5.5V, while the digital supply runs from 3.3V to 5.5V (cite:,). This split-rail architecture means the codec can interface directly with 3.3V logic controllers without a level shifter, but the analog rail must be clean — a linear regulator feeding the 5V analog pin is the usual practice.
It is listed as RoHS non-compliant (cite:), so check your assembly's RoHS exemption policy before committing the BOM.