Help understand spec sheet for EEPROM IC

[andrew.grimm3]

I'm looking to replace a Dallas Memory Module in a CPU circuit with a parallel EEPROM 28C16 IC. I pulled up several spec sheets for a 28C16 and it says that its data retention is 10 years. What exactly does this mean? Does this mean that the data will only be stored for 10 years? The Dallas Memory Module relies on a internal battery that eventually will discharge and my reasoning for replacing with a parallel EEPROM was because of this but if the EEPROM will only last 10 years, it might not be worth the change. Can anyone help me out?

Thanks,

- Andrew

 

[SteamKing]

It means that after 10 years, the data is subject to go 'Poof!'.
I would check different vendors concerning the 28C16. Thomson SGS claims their device can store data for a minimum of 40 years.
Really, why do you want to keep a grizzled old CPU going more than 10 years? Nostalgia?

 

[andrew.grimm3]

It's actually for a two way radio. I'm a ham, and I have several radio's that were manufactured in the 1980's. There programmable by computer to input the frequency information into the radio. The data is held by a Dallas Memory module and I read a write up online that states that they last about 20 years and then the radio is no longer good. Since it was built in the 1980's I thought I better be getting a EEPROM replacement IC if I want to use my radio's a while longer.

 

[Baluncore]

If the (lithium) internal battery expires then the supported CMOS memory will forget. It is usually possible to buy a fresh replacement module and reprogram it. Some modules have a connection for an external battery that carries the backup load and so extends the life of the internal battery.

An EEPROM stores data as charge in an insulated gate. If too much charge leaks away, the chip forgets. The charge leakage is increased by heat or ionising radiation. With historical equipment I keep a copy of the original EEPROM data as a rolling archive on my computer system. If and when the old equipment gives a checksum error I can refresh all the charges in the EEPROM by rewriting the archived data to the chip.

 

[andrew.grimm3]

Thanks for the replies. Mouser has a EEPROM that has around 100 year data store. I'm going to use those for replacements for the Dallas Memory Module's.