M27C256B 256 Kbit (32Kb 8) UV EPROM and OTP EPROM Feature summary 5V 10% supply voltage in Read operation Access time: 45ns 28 Low power consumption: Active Current 30mA at 5MHz 1 Standby Current 100A FDIP28W (F) Programming voltage: 12.75V 0.25V Programming time: 100s/Word Electronic signature 28 Manufacturer Code: 20h Device Code: 8Dh 1 ECOPACK packages available PDIP28 (B) PLCC32 (C) May 2006 Rev 2 1/24 www.st.com 1Contents M27C256B Contents 1 Summary description 5 2 Device operation 8 2.1 Read mode . 8 2.2 Standby mode 8 2.3 Two-line output control 8 2.4 System considerations 9 2.5 Programming . 9 2.6 PRESTO II programming algorithm 9 2.7 Program inhibit . 10 2.8 Program Verify . 10 2.9 Electronic signature . 10 2.10 Erasure operation (applies for UV EPROM) . 11 3 Maximum rating 12 4 DC and AC parameters 13 5 Package mechanical 19 6 Part numbering 22 7 Revision history . 23 2/24