We have used both the 12C68 and the 14C88 AutoStore devices on production products. The 14C88 is used on a mission-critical transportation product, and we have about a thousand of these in the field.

The Simtek parts work as advertised, and we have not had any reliability problems.

Be warned that properly applying any NVSRAM is non-trivial. You have to make sure that a write cycle is not aborted (i.e. due to processor reset). If this happens, then this could cause a write to an incorrect location.

Also, you have to consider operations that should be atomic, such as writing a value to a buffer and then updating a buffer pointer. This is a multiple write operation, all of which must complete in order to prevent trashing of the buffer or its structure. You need to disable interrupts while performing such an operation, and you should make sure that you have enough power available to complete the operation before you start the operation. This implies that some power monitoring circuitry is needed to provide power health status. This would be on the input side, as opposed to your reset generator that is on the output side. BTW, make sure you use a real reset generator, not an RC network to drive RESET.