Operating features M95080-125
5.1
5.1.1
Supply voltage (V
CC
)
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 Operating conditions in
Section 9: DC and AC parameters ). 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
). 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
device pins.
In order to prevent erroneous instruction decoding and 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 VCC reaches the POR threshold voltage. This threshold is lower than the minimum V
CC
operating voltage (see Operating conditions in
Section 9: DC and AC parameters
).
●
●
●
At power-up, when V
CC following state:
passes over the POR threshold, the device is reset and is in the in Standby Power mode, deselected,
Status Register values:
– The Write Enable Latch (WEL) bit is reset to 0.
– The Write In Progress (WIP) bit is reset to 0.
– The SRWD, BP1 and BP0 bits remain unchanged (non-volatile bits).
It is important to note that the device must not be accessed until V
CC
reaches a valid and stable level within the specified [V
CC
(min), V
CC
(max)] range, as defined under Operating
conditions in Section 9: DC and AC parameters .
When the power supply is turned on, V
CC
rises continuously from V
SS
to V
CC
. During this time, the Chip Select (S) line is not allowed to float but should follow the V therefore recommended to connect the S line to V
CC
Figure 4 ).
CC
voltage. It is Obsolete Product(s) - Obsolete Product(s)
In addition, the Chip Select (S) input offers a built-in safety feature, as the S input is edgesensitive as well as level-sensitive: after power-up, the device does not become selected until a falling edge has first been detected on Chip Select (S). This ensures that Chip Select
(S) must have been high, prior to going low to start the first operation.
The V
CC
voltage has to rise continuously from 0 V up to the minimum V
CC
operating voltage
defined under Operating conditions in Section 9: DC and AC parameters
, and the rise time must not vary faster than 1 V/µs.
13/38 Doc ID 022569 Rev 1
