By integrating repeater functions with the entire 100BASE-TX physical layer, including MLT-3 functions, the IMR100 device reduces the number of chips required to design unmanaged Fast Ethernet hubs. Each IMR100 device supports four ports, enabling design of an 8-port 100BASE-TX hub using only two chips, as compared with existing solutions, which require up to nine discrete physical layer and repeater chips. The device's asynchronous expansion bus makes it easy to design high-port-count hubs. In addition, the efficient design of the expansion bus allows the use of inexpensive cables and connectors for box-to-box interconnections.

This high level of integration significantly reduces the bill of material cost for 100BASE-TX hubs. "Many of the installed 10/100Mbps network adapters today are only operating at 10Mbps because Fast Ethernet repeaters are too expensive," said Bob Krueger, AMD's vice president of network products. "The IMR100 device will finally make Fast Ethernet hubs affordable, enabling end-users to implement 100Mbps Ethernet widely in their networks."

The IMR100 device also includes comprehensive LED support, providing full monitoring of per-port and repeater attributes. This enables hub makers to configure specialized LED displays to indicate the status of individual ports and their various attributes, as well as global receive activity and global collision frequency.

The device's advanced integration also improves system power consumption. A single-chip CMOS solution, the IMR100 device reduces power consumption by roughly 50 percent, as compared to discrete solutions. This enables designers to build higher-port-count hubs using smaller, less-expensive power supplies.

In addition to enabling 100BASE-TX operation, the IMR100 device can be configured to support fiber-based hub designs. By connecting directly with external fiber optic transceivers, the IMR100 device can support 100BASE-FX operation on a single repeater port or across all four ports.

The IMR100 repeater is compatible with IEEE 802.3u specifications and supports Class II operation.

Availability
The IMR100 (Am79C730) device is currently sampling and is planned for production in Q2 1997. The device is in a 100-pin PQFP package and is priced at $39.85 in lots of 25,000.

AMD is a global supplier of integrated circuits for the personal and networked computer and communications markets. AMD produces processors, flash memories, programmable logic devices, and products for communications and networking applications. Founded in 1969 and based in Sunnyvale, CA, AMD had revenues of $2 billion in 1996. (NYSE: AMD).