AT24C256C
Electrical Characteristics
2. This parameter is ensured by characterization and is not 100% tested.
Figure 4-1.ꢀBus Timing
tHIGH
tF
tR
tLOW
SCL
tSU.STA
tHD.STA
tHD.DAT
tSU.DAT
tSU.STO
SDA In
tBUF
tAA
tDH
SDA Out
4.5
Electrical Specifications
4.5.1
Power-up Requirements and Reset Behavior
During a power-up sequence, the VCC supplied to the AT24C256C should monotonically rise from GND to
the minimum VCC level, as specified in Table 4-1, with a slew rate no faster than 0.1 V/μs.
4.5.1.1 Device Reset
To prevent inadvertent write operations or any other spurious events from occurring during a power‑up
sequence, the AT24C256C includes a Power-on Reset (POR) circuit. Upon power‑up, the device will not
respond to any commands until the VCC level crosses the internal voltage threshold (VPOR) that brings the
device out of Reset and into Standby mode.
The system designer must ensure the instructions are not sent to the device until the VCC supply has
reached a stable value greater than or equal to the minimum VCC level. Additionally, once the VCC is
greater than or equal to the minimum VCC level, the bus master must wait at least tPUP before sending the
first command to the device. See Table 4-4 for the values associated with these power‑up parameters.
Table 4-4.ꢀPower-up Conditions(1)
Symbol
Parameter
Min. Max. Units
tPUP
Time required after VCC is stable before the device can accept commands 100
－
1.5
—
µs
V
VPOR Power-on Reset Threshold Voltage
—
tPOFF Minimum time at VCC = 0V between power cycles
500
ms
Note:ꢀ
1. These parameters are characterized but they are not 100% tested in production.
If an event occurs in the system where the VCC level supplied to the AT24C256C drops below the
maximum VPOR level specified, it is recommended that a full power cycle sequence be performed by first
driving the VCC pin to GND, waiting at least the minimum tPOFF time and then performing a new power-up
sequence in compliance with the requirements defined in this section.
DS20006042A-page 11
Datasheet
© 2018 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
