AS2523-T

Overview

The AS2523-T is a CMOS integrated circuit designed for A/B-line powered telephony applications, featuring a serial interface and enhanced voice switching capabilities. It incorporates DC and AC line adaptation with synthesized AC-impedance of 1000 ohms, speech circuits with softclipping, and line loss compensation. The device supports handset and handsfree operation, offering programmable Tx/Rx gain and digital volume control via its serial interface. Operating currents range from 15mA to 100mA in normal mode, or 5mA to 15mA with reduced performance. It is available in a 28-pin SOIC package.

Feature Summary

• Integrated serial interface for CPU-controlled configuration of gain, volume, and line loss compensation settings.
• Enhanced voice switching circuit with background noise monitoring and dual softclipping for both handset and handsfree modes.
• Automatic line loss compensation functionality to maintain signal integrity across varying line conditions.
• Programmable complex impedance and side tone adaptation using external components for precise line matching.

Applications

• Enhanced handsfree feature phones with CallerID support
• Telephones with extended displays requiring CPU integration
• A/B-line powered communication devices

Procurement Notes

Verify the specific suffix 'T' corresponds to the 28-pin plastic SOIC surface-mounted package as listed in the ordering information. Confirm that the serial interface requirement aligns with the AS2523 variant rather than the parallel interface variants (AS2524/2524B). Ensure compatibility with the required operating current range and voltage levels specified in the datasheet.

Selection Notes

Select the AS2523-T when a microcontroller-based serial interface is preferred for flexible gain and volume programming. Choose this variant over AS2524/2524B if line loss compensation needs to be programmable rather than fixed. Consider the 28-pin SOIC package constraints and ensure sufficient board space for the required external components for impedance and side tone adjustment.

Part Context

The AS2523 is part of the AS2523/24 family developed by austriamicrosystems AG (now ams AG). It shares the same die with the AS2524 and AS2524B models, differing primarily in interface type and feature activation. The AS2523 specifically enables full software configurability through its serial port, distinguishing it from the hardware-configured parallel interface counterparts.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material. The AS2523 shares the same die as AS2524 and AS2524B; however, interface differences (Serial vs. Parallel) and feature variations (programmable LLC vs. fixed) must be evaluated before considering cross-model substitution.

FAQ

How is Line Loss Compensation (LLC) handled on the AS2523 compared to other variants?

On the AS2523, Line Loss Compensation is programmable via the serial interface registers. In contrast, it is not activated on the AS2524 and is permanently activated at high threshold on the AS2524B.

What is the default operating mode after power-up for the AS2523?

The default setting after power-up is handset mode. The register contents are lost if VDD drops, so registers must be re-written after each hook event or power-up.

Can the transmit and receive gains be adjusted on the AS2523?

Yes, the AS2523 allows programmable Tx and Rx gain adjustments via its serial interface registers, whereas the AS2524/2524B have fixed default gains unless modified by hardware bonding options.