Datasheet

M24256-BF, M24256-BR, M24256-BW, M24256-DR Signal description
Doc ID 6757 Rev 21 9/42
2.5 V
SS
ground
V
SS
is the reference for the V
CC
supply voltage.
2.6 Supply voltage (V
CC
)
2.6.1 Operating supply voltage V
CC
Prior to selecting the memory and issuing instructions to it, a valid and stable V
CC
voltage
within the specified [V
CC
(min), V
CC
(max)] range must be applied (see Tabl e 8, Ta bl e 9 and
Tabl e 1 0 ). In order to secure a stable DC supply voltage, it is recommended to decouple the
V
CC
line with a suitable capacitor (usually of the order of 10 nF to 100 nF) close to the
V
CC
/V
SS
package pins.
This voltage must remain stable and valid until the end of the transmission of the instruction
and, for a Write instruction, until the completion of the internal write cycle (t
W
).
2.6.2 Power-up conditions
V
CC
has to rise continuously from 0 V up to V
CC
(min) (see Tabl e 8, Ta bl e 9 and Tabl e 10 ),
and the rise time must not vary faster than 1 V/µs.
2.6.3 Device reset
In order to prevent inadvertent write operations during power-up, a power on reset (POR)
circuit is included. At power-up, the device does not respond to any instruction until V
CC
reaches an internal reset threshold voltage. This threshold is lower than the minimum V
CC
operating voltage defined in Tabl e 8 , Tabl e 9 and Table 10 .
When V
CC
passes over the POR threshold, the device is reset and enters the Standby
Power mode. However, the device must not be accessed until V
CC
reaches a valid and
stable V
CC
voltage within the specified [V
CC
(min), V
CC
(max)] range.
In a similar way, during power-down (continuous decrease in V
CC
), as soon as V
CC
drops
below the power on reset threshold voltage, the device stops responding to any instruction
sent to it.
2.6.4 Power-down conditions
During power-down (where V
CC
decreases continuously), the device must be in the Standby
Power mode (mode reached after decoding a Stop condition, assuming that there is no
internal Write cycle in progress).