AS2540TR

Overview

The AS2540 is a CMOS integrated circuit designed as a single-chip solution for remote-controlled telephones. It integrates a speech circuit with line adaptation, 2/4-wire conversion, and separate receive/transmit amplifiers for handset and modem paths. The device includes a multi-frequency dialler, ring frequency detector, and a three-tone ring melody generator. Communication with a main-powered CPU is facilitated via a two-wire serial interface operating at 9600 baud. The IC functions as an A/B-line-powered device, supporting both main power mode and a backup mode for independent operation during power failures.

Feature Summary

• Integrated speech circuit providing line adaptation, 2/4-wire conversion, and dedicated amplifiers for handset and modem applications.
• Built-in multi-frequency dialler capable of generating DTMF tones for digits 0-9, *, and #.
• Dual-mode operation allowing transition between main power control and independent backup dialling during power loss.
• Three-tone ring melody generator with ring frequency discrimination to detect valid incoming signals.

Applications

• Web Telephones
• Answering Machines
• Fax Machines
• Base Station of Cordless Telephones
• Hospital Communication Units

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation. The datasheet identifies the SOIC package variant with the suffix T. Confirm that the TR designation aligns with the standard tube or reel packaging options listed in the official ordering information section. Ensure compatibility with the required 28-SOIC footprint and pin configuration before finalizing procurement.

Selection Notes

Select this component for designs requiring a complete analog telephone interface on a single chip. The device supports operation from 15mA to 100mA, with reduced performance available down to 5mA. Consider the 28-pin SOIC package constraints and the requirement for an external ceramic resonator at 3.58MHz. Verify that the system architecture can support the necessary serial interface communication for mode switching and status reporting.

Part Context

The AS2540 is manufactured by ams OSRAM AG, formerly austriamicrosystems AG. It belongs to the family of single-chip telephone interface solutions designed to simplify the integration of analog telephony functions into digital systems. The device replaces multiple discrete components by consolidating line interface, speech processing, and signaling generation into one CMOS IC.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Consult the manufacturer for current obsolescence notices or recommended alternative devices if this part is discontinued.