AN1000 Application note Reduced footprint ZEROPOWER® and TIMEKEEPER® supervisor surface-mount solution Introduction The ZEROPOWER® and TIMEKEEPER® supervisors from STMicroelectronics (such as the M40Z300W and the M48T201V/Y) offer all the advantages of using surface-mount technology, and are well suited to automatic assembly-line processes. Designed to be highly modular, they interface directly with commodity SRAM, and use a commercially available cell for the internal battery (which is easily replaceable). These devices are designed for lower system costs when compared to designs using competitors’ hybrid products. Moreover, even though the ST products need an external SRAM chip, the footprint of the two chips together is still 80% of that of the competitors’ single chip solutions. Figure 1 compares the footprint of a competitor’s chip (not unlike MAXIM/Dallas Semiconductor’s hybrid surface-mount PowerCap module) with an ST device connected to a 1Mbit (128K x 8) low power SRAM chip (perhaps from Hitachi, Sony or Samsung). The former solution might have a footprint of 0.965 by 0.930 inches (0.898 square inches), while the latter leads to a combined footprint of 0.916 by 0.787 inches (0.721 square inches). Figure 1. Footprint comparison 0.965 inches 0.916 inches 0.787 inches 0.697 inches 0.930 inches 0.453 inches SOH28 Competitor’s solution SRAM AI02446 October 2011 Doc ID 5979 Rev 2 1/3 www.st.com Revision history AN1000 Revision history Table 1. 2/3 Document revision history Date Revision Changes Nov-2001 1 Initial release. 04-Oct-2011 2 Updated title, products, Figure 1; revised document presentation. Doc ID 5979 Rev 2 AN1000 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such third party products or services or any intellectual property contained therein. UNLESS OTHERWISE SET FORTH IN ST’S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. UNLESS EXPRESSLY APPROVED IN WRITING BY TWO AUTHORIZED ST REPRESENTATIVES, ST PRODUCTS ARE NOT RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY, DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER’S OWN RISK. Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any liability of ST. ST and the ST logo are trademarks or registered trademarks of ST in various countries. Information in this document supersedes and replaces all information previously supplied. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. © 2011 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com Doc ID 5979 Rev 2 3/3