GENERAL DESCRIPTION

The Am79C98 Twisted-Pair Ethernet Transceiver (TPEX) is an integrated circuit that implements the medium attachment unit (MAU) functions for the twisted-pair medium, as specified by the IEEE 802.3 standard (Type 10BASE-T). This device provides the necessary electrical and functional interface between the IEEE 802.3 standard attachment unit interface (AUI) and the twisted-pair cable.

A network based on the 10BASE-T standard can use unshielded twisted-pair cables, providing an economical solution to networking by allowing the use of exist ing telephone wiring.The Am79C98 provides a minimal component count and cost-effective solution to the design and implementation of 10BASE-T standard networks.

DISTINCTIVE CHARACTERISTICS

■ CMOS device provides compliant operation and low operating current from a single +5 V supply

■ Power Down mode provides reduced power consumption for battery-powered applications.

Reset capability allows use in remote MAU applications.

■ Pin-selectable twisted-pair receive polarity detection and automatic inversion of the receive signal. Polarity indication output pin can directly drive an LED.

■ Pin-selectable twisted-pair Link Integrity Test capability conforming to the IEEE 802.3 standard for 10BASE-T. Link status pin can directly drive an LED.

■ Internal twisted-pair transmitter digital predistortion circuit reduces medium-induced jitter and ensures compliance with the 10BASE-T transmit and receive waveform requirements

■ Pin-selectable SQE Test (heartbeat) enable

■ Transmit and receive status indications are available on separate, dedicated pins

■ AUI loopback, Jabber Control, and SQE Test functions comply with the 10BASE-T standard IEEE Std 802.3i-1990