AS2522B

Overview

The AS2522B is a CMOS integrated circuit designed for telephone line interface and speakerphone applications. It integrates DC and AC line adaptation, speech circuits with softclipping, and line loss compensation for both handset and handsfree modes. The device operates as an A/B-line powered unit controlled via a serial interface. Key functional blocks include a DTMF dialer, FSK transmitter (supporting V.23, BELL202, V.21, BELL 103), and programmable tone ringer. It features enhanced voice switching, background noise monitoring, and programmable Tx/Rx gains. The IC is available in a 32-pin TQFP package.

Feature Summary

• Integrated DTMF generator and FSK transmitter supporting multiple standard protocols
• Enhanced voice switching with three states: idle, transmit, and receive
• Programmable gain control for both transmit and receive paths in handset and handsfree modes
• Automatic line loss compensation to maintain signal integrity over varying line conditions

Applications

• Enhanced handsfree feature phones with CallerID capabilities
• Telephones with extended displays
• Speakerphone systems requiring full two-way communication

Procurement Notes

Verify the specific revision suffix (e.g., Q for TQFP) against current manufacturer availability. Confirm that the component meets the required environmental specifications for normal commercial applications, as extended temperature ranges or high-reliability military/medical uses require additional processing by the manufacturer.

Selection Notes

Select the AS2522B when a single-chip solution for telephone line interface and audio processing is required. Ensure the design supports the necessary external components for synthesizing AC impedance and configuring side tone balance. Verify compatibility with the host CPU's serial interface timing requirements for register configuration.

Part Context

The AS2522B belongs to the AS2522 series of telephone line interface and speakerphone circuits manufactured by ams AG (formerly austriamicrosystems AG). This series provides comprehensive analog and digital functions for traditional landline telephony systems, integrating line driving, audio mixing, and signaling generation into a single CMOS IC.

Replacement Considerations

The AS2522A is a related variant within the same family. Differences may exist in specific register configurations or factory test modes. Verify pinout compatibility and functional equivalence before substitution.