TN0440 Datasheet, PDF (3/6 Pages) STMicroelectronics – M24256 and M24512 EEPROM devices

TN0440
M24xxx EEPROM: 400 kHz and 1 MHz clock
1.2
M24xxx 1 MHz AC tables after 2007
The M24xxx devices running with a 1 MHz clock frequency were introduced by
STMicroelectronics from year 2007. Here again, the M24xxx compatible with the new 1 MHz
I²C-bus specification were designed with timings able to offer the best performances.
Now, when comparing the 1 MHz I²C-bus specification and the M24xxx AC table, the t_CLQV
and t_NS timing values are as shown in Table 3:
Table 3. Access time and Noise filter parameters specified in the 1 MHz AC table
Symbol Alt
Parameter
M24xxx
I²C-bus
Unit
Min. Max. Min. Max.
t_CLQV
t_CLQX
t_AA
Data valid time
t_HD:DAT Data out hold time
- 500 - 450 ns
50 (or
more)
-
0
- ns
t_NS
t_SP
Pulse width ignored (input filter on SCL and
SDA)
50 (or
more)
0
50 ns
• t_CLQX(min) is here again specified with a positive value (as this offers a safe timing
condition, as explained for the previous 400 kHz table).
• t_NS is now equal or better than the value defined in the I²C-bus specification.
1.3
Compatibility of 400 kHz and 1 MHz AC timing specifications
It is important to note that:
• all M24xxx products specified at 1 MHz can run at lower frequencies, and therefore can
run at 400 kHz ;
• old products designed only for the 400 kHz AC tables (AC tables before 2007) cannot
run at 1 MHz.
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