S-93C46A Datasheet, PDF (28/53 Pages) Seiko Instruments Inc – CMOS SERIAL E2PROM

Collection of Product FAQs
Author: Ebisawa Takashi
Date: 99/01/13 (Wednesday) 18:19 (modified: 99/01/14)
<Information level>
A:
Public (Printing O.K.)
Index:
C: quality, reliability
<Product>
Division name: 01 IC
Category 1: 12 Memory
Category 2:
Cal No.:
2. Serial EEPROM
Overall
Related documents:
Question:
What about the reliability and quality of the EEPROM?
Answer:
1. The EEPROM must have a quality that is “special in a sense” and that differs from that of the other
ICs.
<What is this special quality?>
(1) Number of possible rewrites: 105 or 106
A specified minimum number of data rewrites must be assured.
(2) Data retention: 10 years
It must be ensured that written data (‘1’ and ‘0’) will be stored for at least 10 years.
Ensuring (1) and (2) is very difficult in a technical sense, as well as in the sense that high quality must
be maintained despite the need for mass production.
2. Why this guarantee is technically difficult
As shown in the figure below, the EEPROM functions as a non-volatile memory by holding charges
in FG.
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