[volt-nuts] HP-3458A NVRAM

[Randy Evans]

Does anyone know if the DS1220AD will work as a direct replacement for
the DS1220Y
NVRAM chip currently installed in the HP-3458A?  There is a timing
difference between the two devices, as explained in Maxim AN 202.

"the "Y" parts had a reset timeout on the order of milliseconds while the
"AD"
parts have a timeout of 125ms. When replacing the Y part with the AD part,
it must be determined that
the controlling processor does not become active during a power-up cycle
for at least 125ms to ensure
that the NV SRAM is available before the processor attempts a memory
access."

There have been documented cases where the new DS1220AD part will not work
in circuits designed with the DS1220Y (now discontinued).

I would like to know if anyone has successfully utilized the DS1220AD
before proceeding to buy the parts.  Similar question for the DS1230Y and
DS1230AD.

Thanks,

Randy Evans