The scrubbing rate depends on failure intensity and desired reliability.
The approximate equation to determine the LMB memory scrubbing rate is given by the following equation.
Figure 1. LMB Memory Scrubbing
where PW is the probability of an uncorrectable error in a memory word, BER is the soft error rate for a single memory bit, and SR is the Scrubbing Rate.
The soft error rates affecting block RAM for each product family can be found in the Device Reliability Report (UG116).