Modem Analog Front-End

Use in Multiregional Applications with a Single Bill of Materials


The 73M1903C analog front-end (AFE) IC includes fully differential hybrid driver outputs, which connect to the telephone line interface through a transformer-based DAA. The receive pins are also fully differential for maximum flexibility and performance. This arrangement allows for the design of a high-performance hybrid circuit to improve signal-to-noise performance under low receive level conditions, and compatibility with any standard transformer intended for PSTN communications applications.

The 73M1903C device incorporates a digital host interface that is compatible with the serial ports found on most commercially available DSPs and processors and exchanges both payload and control information with the host. This interface can be configured as a single master/slave mode or as a daisy-chain mode that allows the user to connect up to eight 73M1903C devices to a single host for multiple AFE applications such as central server modems.

Key Features

  • Two Pairs of Software-Selectable Transmit Differential Outputs for Worldwide Impedance Driver Implementations
  • Up to 56kbps (V.92) Performance
  • Programmable Sample Rates (7.2kHz to 16.0kHz)
  • Reference Clock Range of 1MHz to 40MHz
  • Crystal Frequency Range of 4.9MHz to 27MHz
  • Master or Slave Mode Operation
  • Daisy-Chain Configurable Synchronous Serial Host Interface
  • Low Power Modes
  • Fully Differential Receiver and Transmitter
  • Drivers for Transformer Interface
  • 3.0V to 3.6V Operation
  • 5V Tolerant I/O
  • Industrial Temperature Range (-40°C to +85°C)
  • JATE-Compliant Transmit Spectrum


  • Automatic Teller Machines
  • Central Site Server Modems
  • Fax Machines
  • Game Consoles
  • Internet Appliances
  • Multifunction Peripherals (MFPs)
  • Personal Video Recorders (PVRs)
  • POS Terminals
  • Set-Top Boxes

Technical Documents

App Note 5020 Software-Based Ring/LIU/PPU Detection
App Note 5017 Test Results for Energy and Voltage Parallel Pick-Up and Line-In-Use Detection

Quality and Environmental Data

Request Reliability Report for: 73M1903C 
Lead-Free Package Tin (Sn) Whisker Reports

Related Resources

Type ID Title
Evaluation Board689473M1903C-EVM 73M1903C Evaluation Board