A25LS512A datasheet(28/43 Pages) AMICC

28 / 43 page

A25LS512A Series

(November, 2014, Version 1.1)

AMIC Technology Corp.

POWER-UP AND POWER-DOWN

At Power-up and Power-down, the device must not be

selected (that is Chip Select ( S ) must follow the voltage

applied on VCC) until VCC reaches the correct value:

VCC (min) at Power-up, and then for a further delay of tVSL

VSS at Power-down

Usually a simple pull-up resistor on Chip Select ( S ) can be

used to insure safe and proper Power-up and Power-down.

To avoid data corruption and inadvertent write operations

during power up, a Power On Reset (POR) circuit is included.

The logic inside the device is held reset while VCC is less than

the POR threshold value, VWI – all operations are disabled,

and the device does not respond to any instruction.

Moreover, the device ignores all Write Enable (WREN), Page

Program (PP), Sector Erase (SE), Block Erase (BE), Chip

Erase (CE) and Write Status Register (WRSR) instructions

until a time delay of tPUW has elapsed after the moment that

VCC rises above the VWI threshold. However, the correct

operation of the device is not guaranteed if, by this time, VCC

is still below VCC(min). No Write Status Register, Program or

Erase instructions should be sent until the later of:

tPUW after VCC passed the VWI threshold

- tVSL afterVCC passed the VCC(min) level

These values are specified in Table 8.

If the delay, tVSL, has elapsed, after VCC has risen above

VCC(min), the device can be selected for Read instructions

even if the tPUW delay is not yet fully elapsed.

At Power-up, the device is in the following state:

The device is in the Standby mode (not the Deep

Power-down mode).

The Write Enable Latch (WEL) bit is reset.

Normal precautions must be taken for supply rail decoupling,

to stabilize the VCC feed. Each device in a system should

have the VCC rail decoupled by a suitable capacitor close to

the package pins. (Generally, this capacitor is of the order of

0.1µF).

At Power-down, when VCC drops from the operating voltage,

to below the POR threshold value, VWI, all operations are

disabled and the device does not respond to any instruction.

(The designer needs to be aware that if a Power-down occurs

while a Write, Program or Erase cycle is in progress, some

data corruption can result.)

Figure 21. Power-up Timing

time

CC(max)

CC(min)

PUW

Full Device Access

VSL

Read

Access

allowed

Reset

State

A25LS512A Datasheet(PDF) 28 Page - AMIC Technology

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