AM79C989JC/T

Overview

The AM79C989JC/T is an Integrated Multiport Repeater Plus (IMR+) chip manufactured by Advanced Micro Devices. It provides a system-level solution for designing IEEE 802.3 compliant repeaters incorporating 10BASE-T transceivers. The device integrates repeater functions specified by Section 9 of the IEEE 802.3 standard and twisted-pair transceiver functions complying with the 10BASE-T standard. It features eight integral twisted-pair medium attachment units (MAUs) and an attachment unit interface (AUI) port, housed in an 84-pin plastic leaded chip carrier (PLCC).

Feature Summary

• Integrates eight 10BASE-T transceivers utilizing predistortion transmission techniques.
• Interfaces directly with the Am79C987 HIMIB device to build fully managed multiport repeaters.
• Includes on-board PLL, Manchester encoder/decoder, and FIFO buffers.

Applications

• Designing compliant 802.3 multiport repeaters.
• Connecting 10BASE-5 (Ethernet) and 10BASE-2 (Cheapernet) networks via AUI.
• Linking 10BASE-F and Fiber Optic Inter-Repeater Link (FOIRL) segments.

Part Context

This component is part of AMD's IMR+ family, serving as an enhanced version of the Am79C980. It maintains pin/socket compatibility with the Am79C980 while adding management port features and minimum mode support for extra LED outputs per port. The device operates on a single +5 V supply, offering high integration and low power consumption typical of CMOS technology.

Replacement Considerations

The AM79C989JC/T is pin/socket-compatible with the Am79C980 IMR chip. Designers can utilize the Am79C980 as a direct substitute in existing designs due to full backward compatibility, though the replacement lacks the additional management port features and LED output support found in the AM79C989JC/T.