The Atmel 3-Volt EPROM Family * Why 3-volt operation? * Does the whole system have to be operated at 3 volts? * How do you program a 3-volt EPROM? * What happens if you run a 3-volt device at 3.6 volts? The Atmel AT27LVxxxA series of EPROMs was designed to operate over a wide range of supply voltages from 3.0 to 3.6 volts. This offers the designer the opportunity to take advantage of the greatly reduced power consumption at 3 volts. The 3-volt series of EPROMs is specified to draw a maximum of 8.0 mA at 5.0 MHz when operated at 3.6VDC. This is less than half of the specified maximum current of a standard EPROM operating at 5.0VDC. Because of the low supply voltage, the power savings calculations are even more dramatic: 29 mW for the LV series compared to 165 mW (5.5V @ 30 mA; i.e. 27C040) for standard fivevolt devices. That means much longer battery life. The LV series has CMOS inputs and outputs specified for TTL levels and 3volt CMOS levels (Rail-to-Rail). In other words, an LV device with VCC = 3.0VDC can drive standard 5-volt TTL logic devices on its data output lines making interface with 5-volt logic easy. The LV series of EPROMs can even be safely driven by 5-volt signals, even though their V CC is at 3.0VDC (please refer to application note Interfacing Atmel LV EPROMs on a Mixed Three-Volt/FiveVolt Data Bus , this chapter). The next question that comes to mind is "Why run just one EPROM at 3 volts while the rest of the system uses 5 volts?" One reason is if your system is on a very tight power budget, such as battery operated equipment, daughter boards or phone line powered products, the six times power savings might make a significant difference. Of course your design might use more than one EPROM, for map memory, operating system, font storage or maybe smart cards. In this case the total power savings can be very large. Remember at 165 mW each, 8 EPROMs at 5 volts use 1.3 Watts instead of 235 mW for the 3-volt devices! When the 3-volt devices are in a programmer they work just like their standard Atmel 5-volt counterparts. Absolutely no difference! Programming support is already in place and widely available on most programmers on the market today. The AT27LVxxxA series of EPROMs are specified to operate from 3.0 to 3.6 volts. So what happens when the device is operated above 3 volts? It speeds up and draws more power, but never more than a standard EPROM. This feature offers the most flexibility for system manufacturers. Low Voltage OTP EPROM CMOS EPROM Rev. 0546A-10/98 1 2 EPROM 3 Atmel Headquarters Atmel Operations Corporate Headquarters Atmel Colorado Springs 2325 Orchard Parkway San Jose, CA 95131 TEL (408) 441-0311 FAX (408) 487-2600 Europe 1150 E. Cheyenne Mtn. Blvd. Colorado Springs, CO 80906 TEL (719) 576-3300 FAX (719) 540-1759 Atmel Rousset Atmel U.K., Ltd. Coliseum Business Centre Riverside Way Camberley, Surrey GU15 3YL England TEL (44) 1276-686677 FAX (44) 1276-686697 Zone Industrielle 13106 Rousset Cedex, France TEL (33) 4 42 53 60 00 FAX (33) 4 42 53 60 01 Asia Atmel Asia, Ltd. Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon, Hong Kong TEL (852) 27219778 FAX (852) 27221369 Japan Atmel Japan K.K. Tonetsu Shinkawa Bldg., 9F 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan TEL (81) 3-3523-3551 FAX (81) 3-3523-7581 Fax-on-Demand North America: 1-(800) 292-8635 International: 1-(408) 441-0732 e-mail literature@atmel.com Web Site http://www.atmel.com BBS 1-(408) 436-4309 (c) Atmel Corporation 1998. Atmel Cor poration makes no warranty for the use of its products, other than those expressly contained in the Company's standard warranty which is detailed in Atmel's Terms and Conditions located on the Company's website. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual proper ty of Atmel are granted by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel's products are not authorized for use as critical components in life suppor t devices or systems. Marks bearing (R) and/or TM are registered trademarks and trademarks of Atmel Corporation. Terms and product names in this document may be trademarks of others. Printed on recycled paper. 0546A-10/98/xM