MB85RS4MT

18

DS501-00053-3v1-E

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NOTE ON USE

We recommend programming of the device after reflow. Data written before reflow cannot be guaranteed.

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Read/Write endurance about FeRAM

The value for Read/Write endurance apply to the total number of read and write operations per row in

FeRAM. This is because FeRAM needs writing operation after each reading operations.Each row in the

memory array has 32 internal outputs, and 8 outputs are selected by A0 and A1. In continuous Read/Write

operations, after selecting a certain address and automatically incrementing until A0 and A1 change from

(0,0) to (1,1), the Read/Write count endurance count is totaled as one operation. Subsequently, when

incrementing automatically and switching to the next row, each row is counted as a new Read/Write operation.

If /CS is raised and then the same row is selected again, it is counted as the second operation for that row.

As an actual usage example, if you loop through and access only a memory area (64 bytes or 256 bytes)

specified by a specific address in the entire memory area, the number of years it will take to reach 1014times

is as below.

As shown here, with a write endurance of 1014 times, even in extreme cases there is enough time before

the upper limit is reached, and under normal conditions of use it can be used without worrying about the

number of writes/reads.

Operating

frequency

Years reached when looping con-

tinuously through 64 byte area

Years reached when looping contin-

uously through 256 byte area

40MHz

42.6

164

20MHz

85.1

328

10MHz

170.0

657