AD1981BJST-LV

Overview

The AD1981BJST-LV is an obsolete AC '97 2.3 compatible stereo codec by Analog Devices, housed in a 48-lead LQFP package. It features a 20-bit Sigma-Delta DAC with >90 dB dynamic range and 16-bit ADCs. The device supports full-duplex variable sample rates from 7 kHz to 48 kHz and includes an integrated stereo headphone amplifier. Key specifications include split power supplies (3.3 V digital, 5 V analog), S/PDIF output, and multiple analog inputs for line-in, AUX, CD, and dual microphones.

Feature Summary

• Integrated stereo headphone amplifier with automatic jack sense switching
• Built-in digital equalizer function for optimized speaker sound
• Software-programmable VREFOUT for biasing external components
• Support for variable sample rates with 1 Hz resolution

Applications

• AC '97 compliant desktop audio systems
• All-in-one PC multimedia solutions
• Consumer electronics requiring integrated stereo codecs

Procurement Notes

This component is officially classified as obsolete by the manufacturer. Verification of authenticity is critical when sourcing from secondary markets. Buyers must confirm the specific ordering suffix matches the required voltage and package variant. Availability is limited to existing stock or surplus channels rather than active manufacturing lines.

Selection Notes

Select this part only for legacy AC '97 architecture designs where backward compatibility is mandatory. Verify that the system requires the specific 5 V analog supply rail, as modern designs often utilize lower voltage standards. Ensure the design accommodates the 48-lead LQFP footprint and thermal requirements specified in the datasheet.

Part Context

The AD1981B series represents Analog Devices' implementation of the AC '97 standard for consumer audio. The 'JST' suffix indicates the specific lead-free LQFP package variant. This codec was designed to replace discrete audio processing chips, consolidating DAC, ADC, and mixing functions into a single integrated circuit for cost-effective motherboard integration.

Replacement Considerations

No direct public substitutes are listed. Designers migrating from this obsolete part should evaluate newer HD Audio codecs or external USB audio interfaces. Compatibility checks regarding pinout and register mapping are required if selecting alternative AC '97 codecs from other manufacturers.