Application Note (AP-438) Revision 1.0 November 2005 Revision History Revision 1.1 0.5 Revision Date Nov 2005 July 2002 Initial Release Initial Release (Confidential) Description Information in this document is provided in connection with Intel products. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Intel's Terms and Conditions of Sale for such products, Intel assumes no liability whatsoever, and Intel disclaims any express or implied warranty, relating to sale and/or use of Intel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. Intel products are not intended for use in medical, life saving, or life sustaining applications. Intel may make changes to specifications and product descriptions at any time, without notice. Designers must not rely on the absence or characteristics of any features or instructions marked "reserved" or "undefined." Intel reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to them. The 8255x Controllers may contain design defects or errors known as errata which may cause the product to deviate from published specifications. Current characterized errata are available on request. Contact your local Intel sales office or your distributor to obtain the latest specifications and before placing your product order. Copies of documents which have an ordering number and are referenced in this document, or other Intel literature may be obtained by calling 1-800- 548-4725 or by visiting Intel's Web site at http://www.intel.com. Intel® is a trademark or registered trademark of Intel Corporation or its subsidaries in the United States and other countries. Copyright © 2005, Intel Corporation. All rights reserved. * Other product and corporate names may be trademarks of other companies and are used only for explanation and to the owners’ benefit without intent to infringe. Application Note (AP-438) Tuning the 8255x Controller’s Equalizer 1.0 Introduction The goal of this document is to enable the construction of an interface for the 8255x without the use of the 1:1 transformer previously required. This reduces cost and size by eliminating the transformer and replacing it with low cost passive components such as resistors and capacitors. This document, and its associated circuitry, was conceived and developed in response to many requests by our OEM customers involved in embedded designs to reduce component expense and “real estate” use on their boards. These new designs eliminate the need for the relatively large and expensive magnetics module commonly used between PHYs and the RJ45 connectors as well as in backplane and other such direct connect applications. We have developed a simple solution that can be used in a wide variety of such applications with the intent of simplifying the design cycle and reducing development time enabling products to enter the market in a shorter time frame than otherwise might be possible. Since different LAN devices use different DC-biasing and different current source circuits, there is no Read the full Interfacing Intel® 8255x Fast Ethernet Controllers without Magnetics.