73M1903-IMR/F

Overview

The Analog Devices/Maxim Integrated 73M1903-IMR/F is a modem analog front-end (AFE) IC designed for PSTN communications. It features fully differential hybrid driver outputs and receive pins, supporting soft modem and DSP-based implementations up to V.92 (56 kbps). The device incorporates a programmable sample rate circuit with rates from 7.2 kHz to 14.4 kHz via pre-scaler NCO and PLL NCO programming. It includes a digital host interface compatible with serial ports on commercial DSPs and processors. The input reference frequency circuit accepts crystals from 9-27 MHz or external clocks between 9-40 MHz, eliminating the need for dedicated oscillators in many applications.

Feature Summary

• Supports V.92 performance up to 56 kbps with programmable sample rates from 7.2 kHz to 14.4 kHz.
• Fully differential receiver and transmitter with on-board line interface drivers for transformer-based DAA interfaces.
• Flexible clock generation accepting crystal frequencies of 9-27 MHz or external references of 9-40 MHz.
• Host synchronous serial interface operation with 5 V tolerant I/O and industrial temperature range (-40 to +85 °C).

Applications

• Set Top Boxes
• Personal Video Recorders (PVR)
• Multifunction Peripherals (MFP)
• Fax Machines
• Internet Appliances

Procurement Notes

The 73M1903-IMR/F is listed as an End-of-Life (EOL) product by the manufacturer. Verification of current availability should be conducted through authorized distributors, noting that stock may be limited or restricted. Buyers must confirm the specific package option (32-pin QFN or 20-pin TSSOP) matches their design requirements, as the IMR suffix typically denotes the QFN variant, but official datasheet ordering information should be consulted for precise packaging details.

Selection Notes

Select the 73M1903 for designs requiring a complete modem AFE solution with integrated hybrid drivers. Ensure the host processor supports the required synchronous serial interface timing. Verify that the system clock can accommodate the 9-40 MHz reference range. Consider the power-saving modes if battery life is critical. Confirm compatibility with the target transformer-based DAA impedance, typically rated at 600 Ω.

Part Context

The 73M1903 belongs to the Teridian family of modem AFEs, originally developed by Teridian Semiconductor Corporation before its acquisition by Maxim Integrated, now part of Analog Devices. It is pin-compatible with the 73M2901CL/CE modems, facilitating direct upgrades or replacements in existing designs. The device simplifies system integration by combining analog front-end functions with digital control capabilities.

Replacement Considerations

The 73M1903 is EOL. Potential replacements include other Teridian/Analog Devices modem AFEs such as the 73M2901 series, subject to pinout and feature verification. No direct public substitute part numbers are confirmed in the provided source material.