EN27C010-70P

The EN27C010-70P is a 1 megabit UV-erasable electrically programmable read-only memory (EPROM) from Eon Silicon Solution. Organized as 131,072 bytes (128KB) of 8-bit data with 70ns maximum access time, it provides fast, non-volatile program storage for embedded systems. The device is manufactured using CMOS technology, offering low power consumption with 40mA maximum active current and 100µA standby current. The 32-pin ceramic DIP package with quartz window allows the memory to be erased by exposure to short-wave ultraviolet light (2537Å wavelength), enabling repeated programming and erasure cycles — typically at least 100 cycles. Programming is performed by applying 12.5V to the VPP pin along with proper address and data signals, using industry-standard EPROM programming algorithms compatible with standard device programmers. The device operates from a single 5V supply during read operations, with TTL-compatible tri-state outputs that simplify bus-oriented system design. The JEDEC-standard pinout ensures compatibility with other 27C010-series devices, making the EN27C010 a drop-in replacement. Data retention is guaranteed for a minimum of 10 years. The EN27C010-70P is suitable for applications requiring non-volatile program storage, including embedded system firmware, BIOS code, microcontroller program memory, industrial control systems, telecom equipment, medical devices, and aerospace systems where the ability to reprogram in development or field maintenance is required.

The EN27C010 EPROM stores data using floating gate transistor technology, where each memory cell contains a MOSFET with an additional ‘floating gate’ surrounded by insulating oxide. In the erased state, the floating gate has no stored charge, and the transistor conducts normally when its control gate is driven — this represents a logic ‘1’ (EPROMs typically read as all 1s after erasure). Programming the device involves applying elevated voltages (12.5V on VPP, 5V on VCC) to selected memory cells. The high voltage across the thin oxide between the drain and floating gate causes electrons to tunnel through the oxide (Fowler-Nordheim tunneling) and become trapped on the floating gate. These trapped electrons create a negative charge that raises the transistor’s threshold voltage, preventing it from turning on during normal read operation — this represents a logic ‘0’. Because the floating gate is surrounded by high-quality oxide, the trapped electrons remain for years (10+ years data retention) even with power removed. Erasure is accomplished by exposing the chip to ultraviolet light through the quartz window on the package. The UV photons provide enough energy for the trapped electrons to overcome the oxide barrier and return to the substrate, restoring the cell to its erased (all 1s) state. During normal read operation, a 17-bit address on pins A0-A16 selects one of the 131,072 bytes. The chip enable (CE#) and output enable (OE#) pins control device selection and output driving, respectively. When CE# is high, the device enters standby mode with significantly reduced power consumption. The tri-state outputs can be placed in high-impedance mode for connection to shared data buses.

• Embedded system firmware storage
• Microprocessor program memory
• PC BIOS and boot code
• Industrial PLC program storage
• Telecom equipment configuration memory
• Medical device control firmware
• Arcade/game machine program ROMs
• Avionics and military equipment