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W9816G6IH

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W9816G6IH

7.17 Power Down Mode

The Power Down mode is initiated by holding CKE low. All of the receiver circuits except CKE are

gated off to reduce the power. The Power Down mode does not perform any refresh operations;

therefore the device can not remain in Power Down mode longer than the Refresh period (tREF) of the

device.

The Power Down mode is exited by bringing CKE high. When CKE goes high, a No Operation

Command is required on the next rising clock edge, depending on tCK. The input buffers need to be

enabled with CKE held high for a period equal to tCKS(min) + tCK(min).

7.18 No Operation Command

The No Operation Command should be used in cases when the SDRAM is in an idle or a wait state to

prevent the SDRAM from registering any unwanted commands between operations. A No Operation

Command is registered when CS is low with RAS , CAS and WE held high at the rising edge of

the clock. A No Operation Command will not terminate a previous operation that is still executing,

such as a burst read or write cycle.

7.19 Deselect Command

The Deselect Command performs the same function as a No Operation Command. Deselect

Command occurs when CS is brought high, the RAS , CAS and WE signals become don't cares.

7.20 Clock Suspend Mode

During normal access mode, CKE must be held high enabling the clock. When CKE is registered low

while at least one of the banks is active, Clock Suspend Mode is entered. The Clock Suspend mode

deactivates the internal clock and suspends any clocked operation that was currently being executed.

There is a one-clock delay between the registration of CKE low and the time at which the SDRAM

operation suspends. While in Clock Suspend mode, the SDRAM ignores any new commands that are

issued. The Clock Suspend mode is exited by bringing CKE high. There is a one-clock cycle delay

from when CKE returns high to when Clock Suspend mode is exited.

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Publication Release Date:May 05, 2008

Revision A01

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