Figure 4-1. Bus Timing

SCL

SDA In

SDA Out

t

F

t

HIGH

t

LOW

t

R

t

DH

t

AA

t

BUF

t

SU.STO

t

SU.DAT

t

HD.DAT

t

HD.STA

t

SU.STA

4.5

Electrical Specifications

4.5.1

Power-Up Requirements and Reset Behavior

During a power-up sequence, the VCC supplied to the AT24CS32 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

AT24CS32 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

－

µs

VPOR

Power-on Reset Threshold Voltage

－

1.5

V

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 AT24CS32 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.

AT24CS32

Electrical Characteristics

© 2020 Microchip Technology Inc.

Datasheet

DS20006341A-page 11