EPROM erase process

Four different EPROM with 64kByte (512 kBit) were used for the test. Reading was done with a custom reading device. A special software read out the EPROM content every 2 seconds and generated a 256 x 256 pixel gray scale image. Every pixel represents a byte, 0 is shown as black and 255 as white. Before the erasing all bytes of the EPROM were programmed to 0.
The erasing was done with a simple UV EPROM-Eraser.
 
 

AM27C512-150DC AMD CMOS EPROM von 1994

Datasheet extract: "AMD's CMOS process technology provides high speed, low power, and high noise immunity."

ca. 3-4 minutes erasing time
D27512-2 intel NMOS EPROM

ca. 2 minutes erasing time
TMM27512AD-17 TOSHIBA NMOS EPROM von 1988

Datasheet extract: "The TMM27512AD is fabricated with the N-channel silicon double lyer gate MOS technology."

< 2 minutes erasing time
TMS27C512-15JL Texas Instruments CMOS EPROM von 1991

ca. 2 minutes erasing time

 

After 3 minutes all tested EPROMs seemed to be erased when read with 5V. When the voltage is lowered down to 3V, data recovers. A complete erasing was given after 10 minutes.

Interesting are also the shadings (TI & intel). Also can be seen that single bits need much longer than the remaining memory.


  © Robert Rottmerhusen 2010  ♦  Update: 2009-11-25  ♦  feedback☺rottmerhusen.com up English Deutsch