Question
We would like to use the ADM1062 device in an rugged powersupply and have few
questions to you. 1. The data storage of the EEPROM is approximately 10 Years.
Is it possible to reprogram the EEPROM after it lost the data? 2. Is it
possible at power up first to verrify via SMBus the EEPROM data before the
ADM1062 runs (especially verrify the DAC offest setting)? 3. Is there any other
possibility to reach at least 20 Years data retention?
Answer
1) The 10 years would be a typical data retention time for EEPROM, depending on
operating conditions of course. After that you'd have to reprogram the part
again to get another 10 (typical) years. If there were any problems programming
the EEPROM that time, then you'd catch it when doing a verify of the EEPROM
write in the programming procedure.
2) In terms of verifying what is programmed into the part at power up, this is
something that can be done across the SMBus interface by a host processor
running suitable code. The default DAC output values could be read and
verified, and the DAC outputs could be enabled at power up in the ADM1062
EEPROM, or they could be enabled by the host processor after the DAC values
have been verified. The state machine in the ADM1062 could be designed so that
it doesn't enable any supplies, and goes into a wait state, where a SMBJump
command is required to move into the power up sequencing states. The host
processor would be able to read the EEPROM contents, verify them, and then
issue the SMJump instruction to continue the power up sequence.
3) As the EEPROM has a limited data retention time, the key thing to do is to
ensure that the memory is 'refreshed', the how and when strategy of the refresh
will probably vary and depend upon the requirements of the application.