For many years, the 8-lead SOIC package has been the most popular package for serial EEPROMs, but now smaller packages are becoming more and more commonplace. This offers a number of benefits; the reductions in footprint size and component height are some of the more obvious ones. Smaller packages also generally offer a cost advantage over their larger counterparts. Currently, the SOT-23 package is one of the smallest packages available for serial EEPROMs, and its popu- larity has been growing significantly. However, while the SOIC is an industry-standard package available from all major EEPROM vendors, the SOT-23 package is still relatively new, especially in larger memory den- sities. When a new, smaller package is first released by a vendor, there is always an inherent lag before the package becomes available from all vendors. For example, Microchip was the first vendor to offer 32- and 64-Kbit I 2 C™ serial EEPROMs in a 5-lead SOT-23 package and it will take time before other vendors offer similar devices. System designers can use the SOT-23 package and enjoy the associated benefits, or they can maintain a broad list of possible vendors. Now, by combining footprints, both can be done at the same time. AN1420 Adding Flexibility by Using Multiple Footprints for Microwire Serial EEPROMs This idea can also be applied to other 8-lead packages, Author: Chris Parris such as the TSSOP and MSOP, if the application Microchip Technology Inc. allows for a small amount of extra board space to be used. INTRODUCTION FIGURE 1: COMBINED 6-LEAD SOT-23 For many years, the 8-lead SOIC package has been ……