EPROM

An EPROM (rarely EROM), or erasable programmable read-only memory, is a type of memory chip. Unlike a normal programmable read-only memory (PROM), this type of chip can have its information cleared and written again.

EPROMs are cleared by shining ultraviolet light on the clear opening on their top. Some EPROMs can be cleared using only electricity instead of needing ultraviolet light. These are called EEPROMs (standing for electrically erasable programmable read-only memory).

EPROM Media

• 

  An EPROM: the Texas Instruments TMS27C040, a CMOS chip with 4 megabits of storage and 8-bit output (shown here in a 600-mil ceramic dual-in-line package). The TMS27C040 operates at 5 volts, but must be programmed at 13 volts.

• 

  An Intel 1702A EPROM, one of the earliest EPROM types (1971), 256 by 8 bit. The small quartz window admits UV light for erasure.

• 

  A cross-section of a floating-gate transistor

• 

  Atmel AT27C010 - an OTP EPROM

• 

  EPROM memory K573RF1 - 8kbit

• 

  EPROM 8kbit - detail of 4 bits

• 

  A 32 KB (256 Kbit) EPROM.  The -12 suffix indicates this device has a 120 nanosecond access time.

• 

  This 8749 Microcontroller stores its program in internal EPROM.

• 

  Nec 02716 2KBit EPROM